Array Functions

reference

You can use array functions to evaluate arrays, perform computations on elements in an array, and to return a new array based on a transformation.

ARRAY_AGG(`expr`)

Description

This function returns an array of the non-MISSING group values in the input expr, including NULL values.

Arguments

expr: [Required] The group of elements you wish to output in an array.

Return Values

An array of non-MISSING values.

If the input expression is MISSING or if one of the elements in the array is MISSING, then it returns MISSING.

Example

Use ARRAY_AGG to group a list of three items into an array.

SELECT ARRAY_AGG(["abc",1,NULL]) AS array_aggregate;

Results

[
  {
    "array_aggregate": [
      [
        "abc",
        1,
        null
      ]
    ]
  }
]

ARRAY_APPEND(`expr`, `val1`, `val2`, …)

Description

This function takes an array expr and one or more val arguments to return a new array with the specified val argument(s) appended.

It requires a minimum of two arguments and returns an error if there are fewer.

Arguments

expr: [Required] The array to be appended to.
val1, val2, …: [At least 1 is required] The text string(s) to be appended.

Return Values

A new array with the specified val argument(s) appended.

If either of the input argument types are MISSING, then it returns MISSING.

If either of the input argument types are NULL, then it returns NULL.

If the expr argument is not an array, then it returns NULL.

If the expr is in the WHERE clause of a partial index, this function lists the expressions that are implicitly covered.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Use ARRAY_APPEND to add a user to the Public Likes array:

SELECT ARRAY_APPEND(t.public_likes, "Valerie Smith") AS add_user_likes
FROM hotel t
LIMIT 1;

Results

[
  {
    "add_user_likes": [
      "Julius Tromp I",
      "Corrine Hilll",
      "Jaeden McKenzie",
      "Vallie Ryan",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow",
      "Valerie Smith"
    ]
  }
]

ARRAY_AVG(`expr`)

Description

This function takes an array expr as an argument and returns the arithmetic mean (average) of all the non-NULL number values in the array, or NULL if there are no such values.

Arguments

expr: [Required] The array of numbers to be evaluated.

Return Values

A number representing the arithmetic mean (average) of all the non-NULL number values in the array expression.

If there are no number values in array expr, then it returns NULL.

If the input expr is MISSING, then it returns MISSING.

If the array size of expr is 0 (no elements), then it returns NULL.

Any non-number elements in the array expr are ignored.

Example

Use ARRAY_AVG with a set of numbers.

SELECT ARRAY_AVG([0,1,1,2,3,5]) AS array_average;

Results

[
  {
    "array_average": 2
  }
]

ARRAY_BINARY_SEARCH(`expr`, `val`, …)

Description

This function returns the first position of the specified value val within the sorted array expr.

The array position is zero-based, that is, the first position is 0.

This function uses a binary search algorithm. If the array is unsorted, the function may not be able to find the value.

Arguments

expr: [Required] The array you want to search, sorted in SQL++ collation order.
val: [Required] The value whose position you want to find.

Return Values

An integer representing the first position of the input val, where the first position is 0. If the value val occurs more than once within the array expr, only the first position is returned.

It returns -1 if the input val is not found in the array.

If one of the arguments is MISSING, it returns MISSING.

If the input expr is not an array, it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Find which position "Brian Kilback" is in the sorted public_likes array:

SELECT ARRAY_BINARY_SEARCH(ARRAY_SORT(t.public_likes), "Brian Kilback")
AS sorted_position
FROM hotel t
LIMIT 1;

Results

[
  {
    "sorted_position": 0
  }
]

ARRAY_CONCAT(`expr1`, `expr2`, …)

Description

This function takes two or more expr arrays and returns a new array after concatenating the input arrays.

If there are fewer than two arguments, then it returns an error.

Arguments

expression1, expression2, …: [At least 2 are required] The arrays to be concatenated together.

Return Values

A new array, concatenated from the input arrays.

If any of the input expr arguments or one of the array elements are MISSING, then it returns MISSING.

If any of the input expr arguments is NULL, then it returns NULL.

If any of the input expr arguments is not an array, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Use ARRAY_CONCAT to add two people to the Public Likes array:

SELECT ARRAY_CONCAT(t.public_likes, ["John McHill", "Dave Smith"]) AS add_user_likes
FROM hotel t
LIMIT 1;

Results

[
  {
    "add_user_likes": [
      "Julius Tromp I",
      "Corrine Hilll",
      "Jaeden McKenzie",
      "Vallie Ryan",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow",
      "John McHill",
      "Dave Smith"
    ]
  }
]

ARRAY_CONTAINS(`expr`, `val`)

Description

This functions checks if the array expression contains the specified value.

Arguments

expr: [Required] The array to be searched.
val: [Required] The value that is being searched for.

Return Values

If either of the input argument types are MISSING, then it returns MISSING.

If either of the input argument types are NULL, then it returns NULL.

If the expr argument is not an array, then it returns NULL.

If the array expr contains val, then it returns TRUE; otherwise, it returns FALSE.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Use ARRAY_CONTAINS with a Boolean function:

SELECT ARRAY_CONTAINS(t.public_likes, "Vallie Ryan") AS array_contains_value
FROM hotel t
LIMIT 1;

Results

[
  {
    "array_contains_value": true
  }
]

ARRAY_COUNT(`expr`)

Description

This function counts all the non-NULL values in the input expr array.

Arguments

expr: [Required] The array to be searched and evaluate its values.

Return Values

A count of all the non-NULL values in the array, or zero if there are no such values.

If the expr argument is MISSING, then it returns MISSING.

If the expr argument is NULL, then it returns NULL.

If the expr argument is not an array, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Use ARRAY_COUNT to count the total hotel reviews:

SELECT ARRAY_COUNT(t.reviews) AS total_reviews
FROM hotel t
LIMIT 1;

Results

[
  {
    "total_reviews": 2
  }
]

ARRAY_DISTINCT(`expr`)

Description

This function returns a new array with distinct elements of the input array expr.

Arguments

expr: [Required] The array of items to be evaluated.

Return Values

An array with distinct elements of the input array expr.

If the input expr is MISSING, it returns MISSING.

If the input expr is a non-array value, it returns NULL.

Example

Use ARRAY_DISTINCT with a group of items.

SELECT ARRAY_DISTINCT(["apples","bananas","grapes","oranges","apples","mangoes","bananas"])
AS distinct_fruits;

Results

[
  {
    "distinct_fruits": [
      "oranges",
      "grapes",
      "bananas",
      "mangoes",
      "apples"
    ]
  }
]

ARRAY_EXCEPT(`expr1`, `expr2`)

Description

This function returns all the elements of the first array, except for those which are also included in the second array.

Arguments

expr1: [Required] The input array, from which specified elements may be excluded.
expr2: [Required] The array of elements to be excluded.

Return Value

An array of all the elements in expr1, except for those which also occur in expr2.

If any of the arguments is MISSING, it returns MISSING.

If any of the arguments is a non-array, it returns NULL.

Examples

Return an array of even numbers by excluding odd numbers.

WITH Numbers AS ([1, 2, 3, 4, 5, 6]),
Odd AS ([1, 3, 5])
SELECT ARRAY_EXCEPT(Numbers, Odd) AS Even;

Results

[
  {
    "Even": [
      2,
      4,
      6
    ]
  }
]

ARRAY_FLATTEN(`expr`, `depth`)

Description

This function flattens nested array elements into the top-level array, up to the specified depth.

Arguments

expr: [Required] The multilevel array to be flattened.
depth: [Required] The Integer representing the number of depths to flatten.

Return Value

An array with depth fewer levels than the input array expr.

If one of the arguments is MISSING, it returns MISSING.

If the input expr is a non-array, or if the input depth argument is not an integer, it returns NULL.

Examples

Create a 3-level array of numbers to flatten by 1 level.

INSERT INTO default (KEY, value)
             VALUES ("na", {"a":2, "b":[1,2,[31,32,33],4,[[511, 512], 52]]});

SELECT ARRAY_FLATTEN(b,1) AS flatten_by_1 FROM default USE KEYS ["na"];

Results

[
  {
    "flatten_by_1": [
      1,
      2,
      31,
      32,
      33,
      4,
      [
        511,
        512
      ],
      52
    ]
  }
]

Flatten the above example by 2 levels.

SELECT ARRAY_FLATTEN(b,2) AS flatten_by_2 FROM default USE KEYS ["na"];

Results

[
  {
    "flatten_by_2": [
      1,
      2,
      31,
      32,
      33,
      4,
      511,
      512,
      52
    ]
  }
]

ARRAY_IFNULL(`expr`)

Description

This function parses the input array expr and returns the first non-NULL value in the array.

Arguments

expr: [Required] The array of values to be evaluated.

Return Values

The first non-NULL value in the input array.

If the input expr is MISSING, then it returns MISSING.

If the input expr is a non-array, then it returns NULL.

Examples

Find the first non-NULL value in an array of items.

SELECT ARRAY_IFNULL( ["","apples","","bananas","grapes","oranges"]) AS check_null;

Results

[
  {
    "check_null": ""
  }
]

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Find the first non-null hotel reviewers:

SELECT ARRAY_IFNULL(t.public_likes) AS if_null
FROM hotel t
LIMIT 2;

Results

[
  {
    "if_null": "Julius Tromp I"
  },
  {
    "if_null": null
  }
]

ARRAY_INSERT(`expr`, `pos`, `val1`, `val2`, …)

Description

This function inserts the specified value or multiple value items into the specified position in the input array expression, and returns the new array.

Arguments

expr: [Required] The array to insert items into.
pos: [Required] The integer specifying the array position from the left of the input array expr, where the 1st position is 0 (zero).
val1, val2, …: [At least one is required] The value or multiple value items to insert into the input array expression.

Return Values

An array with the input value or multiple value items inserted into the input array expression at position pos.

If any of the three arguments are MISSING, then it returns MISSING.

If the expr argument is a non-array or if the position argument is not an integer, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Insert "jsmith" into the 2nd position of the public_likes array:

SELECT ARRAY_INSERT(public_likes, 2, "jsmith") AS insert_val
FROM hotel
LIMIT 1;

Results

[
  {
    "insert_val": [
      "Julius Tromp I",
      "Corrine Hilll",
      "jsmith",
      "Jaeden McKenzie",
      "Vallie Ryan",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow"
    ]
  }
]

ARRAY_INTERSECT(`expr1`, `expr2`, ...)

Description

This function takes two or more arrays and returns the intersection of the input arrays as the result; that is, the array containing values that are present in all of the input arrays.

Arguments

expr1, expr2, …: [At least 2 are required] The two or more arrays to compare the values of.

Return Values

An array containing the values that are present in all of the input arrays.

If there are no common elements, then it returns an empty array.

If any of the input arguments are MISSING, then it returns MISSING.

If any of the input arguments are non-array values, then it returns NULL.

Examples

Compare three arrays of fruit for common elements.

SELECT ARRAY_INTERSECT( ["apples","bananas","grapes","orange"], ["apples","orange"], ["apples","grapes"])
AS array_intersection;

Results

[
  {
    "array_intersection": [
      "apples"
    ]
  }
]

Compare three arrays of fruit with no common elements.

SELECT ARRAY_INTERSECT( ["apples","grapes","oranges"], ["apples"],["oranges"],["bananas", "grapes"])
AS array_intersection;

Results

[
  {
    "array_intersection": []
  }
]

ARRAY_LENGTH(`expr`)

Equivalent: LEN()

Description

This function returns the number of elements in the input array.

Arguments

expr: [Required] The array whose elements you want to know the number of.

Return Values

An integer representing the number of elements in the input array.

If the input argument is MISSING, then it returns MISSING.

If the input argument is a non-array value, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Find how many total public_likes there are in the travel-sample keyspace:

SELECT ARRAY_LENGTH(t.public_likes) AS total_likes
FROM hotel t
LIMIT 1;

Results

[
  {
    "total_likes": 8
  }
]

ARRAY_MAX(`expr`)

Description

This function returns the largest non-NULL, non-MISSING array element, in SQL++ collation order.

Arguments

expr: [Required] The array whose elements you want to know the highest value of.

Return Values

The largest non-NULL, non-MISSING array element, in SQL++ collation order.

If the input expr is MISSING, then it returns MISSING.

If the input expr is a non-array value, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Find the maximum (last) value of the public_likes array:

SELECT ARRAY_MAX(t.public_likes) AS max_val
FROM hotel t
LIMIT 1;

Results

[
  {
    "max_val": "Vallie Ryan"
  }
]

ARRAY_MIN(`expr`)

Description

This function returns the smallest non-NULL, non-MISSING array element, in SQL++ collation order.

Arguments

expr: [Required] The array whose elements you want to know the lowest value of.

Return Values

The smallest non-NULL, non-MISSING array element, in SQL++ collation order.

If the input expr is MISSING, then it returns MISSING.

If the input expr is a non-array value, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Find the minimum (first) value of the public_likes array:

SELECT ARRAY_MIN(t.public_likes) AS min_val
FROM hotel t
LIMIT 1;

Results

[
  {
    "min_val": "Brian Kilback"
  }
]

ARRAY_MOVE(`expr`, `val1`, `val2`)

Description

This function returns a new array containing all the elements of expr, with one element moved to a new position.

Arguments

expr: [Required] The input array containing an element that you want to move.
val1: [Required] An integer specifying the old location of the element to move.
val2: [Required] An integer specifying the new location of the element to move.

If val1 or val2 are 0 or greater, the position is counted from the left of the input array, where the leftmost position in the array is 0 (zero). If val1 or val2 are less than 0, the position is counted from the right of the input array, where the rightmost position in the array is -1.

Return Values

An array with the element at the position specified by val1 moved to a new position specified by val2.

If either of the val arguments is outside the array, the function returns NULL.

If any of the arguments is MISSING, then it returns MISSING.

If the expr argument is a non-array, or if either of the val arguments is not an integer, then it returns NULL.

Examples

Move the first element in the array to the second position in the array.

WITH Letters AS (["a", "b", "c", "d", "e", "f"])
SELECT ARRAY_MOVE(Letters, 0, 1) AS Second;

Results

[
  {
    "Second": [
      "b",
      "a",
      "c",
      "d",
      "e",
      "f"
    ]
  }
]

Move the first element in an array to the penultimate position in the array.

WITH Letters AS (["a", "b", "c", "d", "e", "f"])
SELECT ARRAY_MOVE(Letters, 0, -2) AS Penultimate;

Results

[
  {
    "Penultimate": [
      "b",
      "c",
      "d",
      "e",
      "a",
      "f"
    ]
  }
]

ARRAY_POSITION(`expr`, `val`)

Description

This function returns the first position of the specified value within the array expression.

The array position is zero-based, that is, the first position is 0.

Arguments

expr: [Required] The array you want to search.
val: [Required] The value whose position you want to know.

Return Values

An integer representing the first position of the input val, where the first position is 0. If the value val occurs more than once within the array expr, only the first position is returned.

It returns -1 if the input val does not exist in the array.

If one of the arguments is MISSING, it returns MISSING.

If either of the arguments are non-array values, it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Find which position "Brian Kilback" is in the public_likes array:

SELECT ARRAY_POSITION(t.public_likes, "Brian Kilback") AS array_position
FROM hotel t
LIMIT 1;

Results

[
  {
    "array_position": 4
  }
]

ARRAY_PREPEND(`val1`, `val2`, … , `expr`)

Description

This function returns the new array after prepending the array expr with the specified val or multiple val arguments.

It requires a minimum of two arguments.

Arguments

val1, val2, …: [At least 1 is required] The value or multiple value arguments to prepend to the input expr.
expression: [Required] The array you want to have the input value argument(s) prepended to.

Return Values

A new array with the input val argument(s) prepended to the input array expr.

If one of the arguments is MISSING, it returns MISSING.

If the last argument is a non-array, it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Prepend "Dave Smith" to the front of the public_likes array:

SELECT ARRAY_PREPEND("Dave Smith",t.public_likes) AS prepend_val
FROM hotel t
LIMIT 1;

Results

[
  {
    "prepend_val": [
      "Dave Smith",
      "Julius Tromp I",
      "Corrine Hilll",
      "Jaeden McKenzie",
      "Vallie Ryan",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow"
    ]
  }
]

ARRAY_PUT(`expr`, `val1`, `val2`, …)

Description

This function returns a new array with val or multiple val arguments appended if the val is not already present. Otherwise, it returns the unmodified input array expr.

It requires a minimum of two arguments.

Arguments

expr: [Required] The array you want to append the input value or value arguments.
val1, val2, …: [At least 1 is required] The value or multiple value arguments that you want appended to the end of the input array expression.

Return Values

A new array with val or multiple val arguments appended if the val is not already present. Otherwise, it returns the unmodified input array expr.

If one of the arguments is MISSING, then it returns MISSING.

If the first argument is a non-array, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Append "Dave Smith" to the end of the public_likes array:

SELECT ARRAY_PUT(t.public_likes, "Dave Smith") AS array_put
FROM hotel t
LIMIT 1;

Results

[
  {
    "array_put": [
      "Julius Tromp I",
      "Corrine Hilll",
      "Jaeden McKenzie",
      "Vallie Ryan",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow",
      "Dave Smith"
    ]
  }
]

ARRAY_RANGE(`start_num`, `end_num` `step_num` ])

Description

This function returns a new array of numbers, from start_num until the largest number less than end_num. Successive numbers are incremented by step_int.

If step_int is not specified, then the default value is 1. If step_num is negative, then he function decrements until the smallest number greater than end_num.

Arguments

start_num: [Required] The integer to start a new array with.
end_num: [Required] The integer that is one number larger than the final integer in the output array.
step_num: [Optional; default is 1] The number between each array element.

If step_num is negative, then the function decrements until the smallest number greater than end_num.

Output Values: A new array of numbers, from start_num until the largest number less than end_num.

If any of the arguments are MISSING, then it returns MISSING.

If any of the arguments do not start with a digit, then it returns an error.

Examples

Make an array from 0 to 20 by stepping every 5th number.

SELECT ARRAY_RANGE(0, 25, 5) AS gen_array_range_5;

Results

[
  {
    "gen_array_range_5": [
      0,
      5,
      10,
      15,
      20
    ]
  }
]

Make an array from 0.1 to 1.1 by stepping every 2nd number.

SELECT ARRAY_RANGE(0.1, 2) AS gen_array_range_2;

Results

[
  {
    "gen_array_range_2": [
      0.1,
      1.1
    ]
  }
]

Make an array from 10 to 3 by stepping down every 3rd number.

SELECT ARRAY_RANGE(10, 3, -3) AS gen_array_range_minus3;

Results

[
  {
    "gen_array_range-3": [
      10,
      7,
      4
    ]
  }
]

ARRAY_REMOVE(`expr`, `val1`, `val2`, …)

Description

This function returns a new array with all occurrences of the specified value or multiple value fields removed from the array expression. It requires a minimum of two arguments.

Arguments

expr

[Required] The input array to have the specified val or multiple val fields removed.

val1, val2, …

[At least 1 is required] The input value or multiple values to remove from the input array expr.

Output Values

A new array with all occurrences of the specified val or multiple val fields removed from the array expr.

If any of the arguments are MISSING, then it returns MISSING.

If the first argument is not an array, then it returns NULL.

This function cannot be used to remove NULL values from an array as it uses an equality predicate when evaluating the array elements to remove. Since NULL does not equal NULL, such values are not matched and remain in the array.

To remove NULL values, use the Array Collection Operator instead. For example:

SELECT ARRAY name FOR name IN ["Ryan", NULL, "Corrine"]
WHEN name IS NOT NULL
END AS filtered_names;

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Remove "Vallie Ryan" from the public_likes array:

SELECT ARRAY_REMOVE(t.public_likes, "Vallie Ryan") AS remove_val
FROM hotel t
LIMIT 1;

Results

[
  {
    "remove_val": [
      "Julius Tromp I",
      "Corrine Hilll",
      "Jaeden McKenzie",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow"
    ]
  }
]

ARRAY_REPEAT(`val`, `rep_int`)

Description

This function returns a new array with the specified val repeated rep_int times.

Arguments

val: [Required] The input value you want repeated.
rep_int: [Required] The integer number of times you want the input val repeated.
Output Values: A new array with the specified val repeated rep_int times.

If any of the arguments are MISSING, then it returns MISSING.

If the rep_int argument is not an integer, then it returns NULL.

Example

Make an array with "Vallie Ryan" three times.

SELECT ARRAY_REPEAT("Vallie Ryan", 3) AS repeat_val;

Results

[
  {
    "repeat_val": [
      "Vallie Ryan",
      "Vallie Ryan",
      "Vallie Ryan"
    ]
  }
]

ARRAY_REPLACE(`expr`, `val1`, `val2` [, `max_int`])

Description

This function returns a new array with all occurrences of value1 replaced with value2.

If max_int is specified, the function performs no more than max_int replacements.

Arguments

expr: [Required] The input array you want to replace val1 with val2.
val1: [Required] The existing value in the input expr you want to replace.
val2: [Required] The new value you want to take the place of val1 in the input expr.
max_int: [Optional. Default is no maximum] The number of maximum replacements to perform.

Return Values

A new array with all or max_int occurrences of val1 replaced with val2.

If any of the arguments are MISSING, then it returns MISSING.

If the first argument is not an array or if the second argument is NULL, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Replace all occurrences of "Vallie Ryan" with "Valerie Ryan":

SELECT ARRAY_REPLACE(t.public_likes, "Vallie Ryan", "Valerie Ryan") AS replace_val
FROM hotel t
LIMIT 1;

Results

[
  {
    "replace_val": [
      "Julius Tromp I",
      "Corrine Hilll",
      "Jaeden McKenzie",
      "Valerie Ryan",
      "Brian Kilback",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Elnora Trantow"
    ]
  }
]

ARRAY_REPLACE_EQUIVALENT(`expr`, `val1`, `val2` [, `max_int`])

Description

This function is similar to the ARRAY_REPLACE() function and returns a new array with all occurrences of val1 replaced with val2. However, it determines matches using the equivalence operator instead of the equality operator. This enables you to replace NULL values and composite object values with NULL attributes, which is not possible with ARRAY_REPLACE().

If max_int is specified, the function performs no more than max_int replacements.

Arguments

expr: [Required] The input array you want to replace val1 with val2.
val1: [Required] The existing value in the input expr you want to replace.
val2: [Required] The new value you want to take the place of val1 in the input expr.
max_int: [Optional] The maximum number of replacements to perform. By default, you can perform any number of replacements.

Return Values

A new array with all or max_int occurrences of val1 replaced with val2.

If any of the arguments are MISSING, then it returns MISSING.

If the first argument is not an array, then it returns NULL.

Example

The following example shows how the ARRAY_REPLACE_EQUIVALENT function can replace NULL values, while the ARRAY_REPLACE function cannot.

SELECT
ARRAY_REPLACE([{"name":"Brian"},{"name":null}],
          {"name":null},
          {"name":"Unknown User"})
          AS replace_result,
ARRAY_REPLACE_EQUIVALENT([{"name":"Brian"},{"name":null}],
          {"name":null},
          {"name":"Unknown User"})
          AS replace_equiv_result;

Results

[
  {
    "replace_result": [
      {
        "name": "Brian"
      },
      {
        "name": null
      }
    ],
    "replace_equiv_result": [
      {
        "name": "Brian"
      },
      {
        "name": "Unknown User"
      }
    ]
  }
]

ARRAY_REVERSE(`expr`)

Description

This function returns a new array with all the elements of expr in reverse order.

Arguments

expr: [Required] The input array whose elements you want to reverse.

Return Values

A new array with all the elements of expr in reverse order.

If the argument is MISSING, then it returns MISSING.

If the argument is a non-array value, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Reverse the values in the public_likes array:

SELECT ARRAY_REVERSE(t.public_likes) AS reverse_val
FROM hotel t
LIMIT 1;

Results

[
  {
    "reverse_val": [
      "Elnora Trantow",
      "Ms. Moses Feeney",
      "Lilian McLaughlin",
      "Brian Kilback",
      "Vallie Ryan",
      "Jaeden McKenzie",
      "Corrine Hilll",
      "Julius Tromp I"
    ]
  }
]

ARRAY_SORT(`expr`)

Description

This function returns a new array with the elements of expr sorted in SQL++ collation order.

Arguments

expr: [Required] The input array you want sorted.

Return Values

A new array with the elements of expr sorted in SQL++ collation order.

If the argument is MISSING, then it returns MISSING.

If the argument is a non-array value, then it returns NULL.

Example

For this example, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Sort the public_likes array:

SELECT ARRAY_SORT(t.public_likes) AS sorted_array
FROM hotel t
LIMIT 1;

Results

[
  {
    "sorted_array": [
      "Brian Kilback",
      "Corrine Hilll",
      "Elnora Trantow",
      "Jaeden McKenzie",
      "Julius Tromp I",
      "Lilian McLaughlin",
      "Ms. Moses Feeney",
      "Vallie Ryan"
    ]
  }
]

ARRAY_STAR(`expr`)

Description

This function converts an array of expr objects into an object of arrays.

Arguments

expr: [Required] The input array you want to convert into an object of arrays.

Output Values

An object of arrays.

If the argument is MISSING, then it returns MISSING.

If the argument is a non-array value, then it returns NULL.

Example

Convert a given array of two documents each with five items into an object of five arrays each with two documents.

SELECT ARRAY_STAR( [
   {
    "address": "Capstone Road, ME7 3JE",
    "city": "Medway",
    "country": "United Kingdom",
    "name": "Medway Youth Hostel",
    "url": "http://www.yha.org.uk"
  },
  {
    "address": "6 rue aux Juifs",
    "city": "Giverny",
    "country": "France",
    "name": "The Robins",
    "url": "http://givernyguesthouse.com/robin.htm"
  }]) AS array_star;

Results

[
  {
    "array_star": {
      "address": [
        "Capstone Road, ME7 3JE",
        "6 rue aux Juifs"
      ],
      "city": [
        "Medway",
        "Giverny"
      ],
      "country": [
        "United Kingdom",
        "France"
      ],
      "name": [
        "Medway Youth Hostel",
        "The Robins"
      ],
      "url": [
        "http://www.yha.org.uk",
        "http://givernyguesthouse.com/robin.htm"
      ]
    }
  }
]

Array References

You can use an asterisk (*) as an array subscript which converts the array to an object of arrays. The following example returns an array of the ages of the given contact’s children:

SELECT children[*].age FROM contacts WHERE fname = "Dave"

An equivalent query can be written using the array_star() function:

SELECT array_star(children).age FROM contacts WHERE fname = "Dave"

Empty Array Subscripts

You can use an empty array subscript ([ ]) to return an array that includes only defined elements.

The rules governing its use are as follows:

Expression Description

Expression	Description
`field[]`	If `field` is not an array, it returns `NULL`. If `field` is an array, it returns the array as is.
`field[][]`	If `field` is not an array, it returns `NULL`. If `field` contains only unnamed arrays, it returns `field` as is. Otherwise, it returns `NULL`.
`field[].field2`	If `field` is not an array, it returns `MISSING`. If `field` is an array, it extracts `field2` from each element in `field` and returns a new array with those values. If `field` contains unnamed arrays, they are flattened by one level. Then from the resulting array, it extracts `field2` from each object where it is present.
`field[][].field2`	If `field` is not an array, it returns `MISSING`. If every element in `field` is not an unnamed array, it returns `MISSING`. If `field` contains unnamed arrays, they are flattened by one level. Then from the resulting array, it extracts `field2` from each object where it is present.
`field[].field2[].field3`	Returns an array of `field3` values by traversing two levels of arrays. First it extracts `field2` from each element of `field`, then extracts `field3` from each element of the resulting `field2` array. If `field` and `field2` contain unnamed arrays, they are flattened by one level. Then from the resulting `field2` array, it extracts `field3` from each object where it is present.

field[]

If field is not an array, it returns NULL.
If field is an array, it returns the array as is.

field[][]

If field is not an array, it returns NULL.
If field contains only unnamed arrays, it returns field as is. Otherwise, it returns NULL.

field[].field2

If field is not an array, it returns MISSING.
If field is an array, it extracts field2 from each element in field and returns a new array with those values.
If field contains unnamed arrays, they are flattened by one level. Then from the resulting array, it extracts field2 from each object where it is present.

field[][].field2

If field is not an array, it returns MISSING.
If every element in field is not an unnamed array, it returns MISSING.
If field contains unnamed arrays, they are flattened by one level. Then from the resulting array, it extracts field2 from each object where it is present.

field[].field2[].field3

Returns an array of field3 values by traversing two levels of arrays. First it extracts field2 from each element of field, then extracts field3 from each element of the resulting field2 array.
If field and field2 contain unnamed arrays, they are flattened by one level. Then from the resulting field2 array, it extracts field3 from each object where it is present.

If you use more that two empty array subscripts (for example, field[][][]), the function considers only the first two subscripts and ignores the rest.

Example

Given the following sample document:

{
  "a": {
    "airline": "AF",
    "airlineid": "airline_003",
    "destinationairport": "SFO",
    "distance": 2481.617376098415,
    "equipment": "320",
    "id": 3,
    "schedule": [
      {
        "day": 0,
        "flight": "AF198",
        "utc": "10:13:00"
      },
      {
        "flight": "AF250",
        "utc": "12:59:00"
      },
      {
        "day": 2,
        "flight": "AF223",
        "special_flights": [
          {
            "a": "SA"
          },
          {
            "b": [
              [
                {
                  "c": "SC1"
                },
                {
                  "c": "SC2"
                }
              ],
              [
                {
                  "c": "SC3"
                }
              ]
            ]
          }
        ],
        "utc": "19:41:00"
      }
    ],
    "sourceairport": "DFW"
  }
}

Here’s how different array subscripts evaluate:

a.airline[]: Returns NULL (not an array).
a.schedule[]: Equivalent to a.schedule, returns the array.
a.schedule[].day: Returns [0, 2]. This is in contrast to a.schedule[*].day, which returns [0, null, 2].
a.schedule[].special_flights[].a: Returns ["SA"].
a.schedule[][].utc: Returns MISSING.
a.schedule[].special_flights[].b[][].c: Returns ["SC1", "SC2", "SC3"].
a.schedule[].special_flights[].b[].c: Also returns ["SC1", "SC2", "SC3"], as the unnamed arrays are flattened.

ARRAY_SUM(`expr`)

Description

This function returns the sum of all the non-NULL number values in the expr array.

Arguments

expr: [Required] The input array of numbers you want to know the total value of.

Return Values

The sum of all the non-NULL number values in the expr array.

If there are no number values, then it returns 0 (zero).

If the argument is MISSING, then it returns MISSING.

If the argument is a non-array value, then it returns NULL.

Example

Find the total of a given array of numbers.

SELECT ARRAY_SUM([0,1,1,2,3,5]) as sum;

Results

[
  {
    "sum": 12
  }
]

ARRAY_SYMDIFF(`expr1`, `expr2`, …)

This function has a synonym ARRAY_SYMDIFF1().

Description

This function returns a new array based on the set symmetric difference, or disjunctive union, of the input expression arrays. The new array contains only those elements that appear in exactly one of the input arrays, and it requires a minimum of two arguments.

Arguments

expr1, expr2, …: [At least 2 are required] The input arrays to compare.

Return Values

A new array containing only those elements that appear in exactly one of the input arrays.

If any of the arguments is MISSING, then it returns MISSING.

If any of the arguments is a non-array value, then it returns NULL.

The difference between ARRAY_SYMDIFF() and ARRAY_SYMDIFFN() is that the former function includes the value when it appears only once, while the latter function includes the value when it appears an odd number of times in the input arrays.

Refer to the following article for more information on the difference between a normal and n-ary symdiff: https://en.wikipedia.org/wiki/Symmetric_difference.

Example

Find the elements that appear in exactly one of these three input arrays.

SELECT ARRAY_SYMDIFF([1, 2], [1, 2, 4], [1, 3]) AS symm_diff1;

Results

[
  {
    "symm_diff1": [
      3,
      4
    ]
  }
]

ARRAY_SYMDIFF1(`expr1`, `expr2`, …)

Synonym of ARRAY_SYMDIFF().

ARRAY_SYMDIFFN(`expr1`, `expr2`, …)

Description

This function returns a new array based on the set symmetric difference, or disjunctive union, of the input arrays. The new array contains only those elements that appear in an odd number of input arrays, and it requires a minimum of two arguments.

Arguments

expr1, expr2, …: [At least 2 are required] The input arrays to compare.

Return Values

A new array containing only those elements that appear in an odd number of the input arrays.

If any of the arguments is MISSING, then it returns MISSING.

If any of the arguments is a non-array value, then it returns NULL.

Refer to the following article for more information on the difference between a normal and n-ary symdiff: https://en.wikipedia.org/wiki/Symmetric_difference.

Example

Find the elements that appear in an odd number of these three input arrays.

SELECT ARRAY_SYMDIFFN([1, 2], [1, 2, 4], [1, 3]) AS symm_diffn;

Results

[
  {
    "symm_diffn": [
      1,
      3,
      4
    ]
  }
]

ARRAY_UNION(`expr1`, `expr2`, …)

Description

This function returns a new array with the set union of the input arrays, and it requires a minimum of two arguments.

Arguments

expr1, expr2, …: [At least 2 are required] The input arrays to compare.

Return Values

A new array with the set union of the input arrays.

If any of the arguments is MISSING, then it returns MISSING.

If any of the arguments is a non-array value, then it returns NULL.

Examples

List the union of three given arrays.

SELECT ARRAY_UNION([1, 2], [1, 2, 4], [1, 3]) AS array_union;

Results

[
  {
    "array_union": [
      3,
      2,
      1,
      4
    ]
  }
]

List the union of two given arrays with a string.

SELECT ARRAY_UNION([1, 2], [1, 2, 4], "abc") AS array_union;

Results

[
  {
    "array_union": null
  }
]

Array Functions

ARRAY_AGG(expr)

Description

Arguments

Return Values

Example

ARRAY_APPEND(expr, val1, val2, …)

Description

Arguments

Return Values

Example

ARRAY_AVG(expr)

Description

Arguments

Return Values

Example

ARRAY_BINARY_SEARCH(expr, val, …)

Description

Arguments

Return Values

Example

ARRAY_CONCAT(expr1, expr2, …)

Description

Arguments

Return Values

Example

ARRAY_CONTAINS(expr, val)

Description

Arguments

Return Values

Example

ARRAY_COUNT(expr)

Description

Arguments

Return Values

Example

ARRAY_DISTINCT(expr)

Description

Arguments

Return Values

Example

ARRAY_EXCEPT(expr1, expr2)

Description

Arguments

Return Value

Examples

ARRAY_FLATTEN(expr, depth)

Description

Arguments

Return Value

Examples

ARRAY_IFNULL(expr)

Description

Arguments

Return Values

Examples

ARRAY_INSERT(expr, pos, val1, val2, …)

Description

Arguments

Return Values

Example

ARRAY_INTERSECT(expr1, expr2, ...)

Description

Arguments

Return Values

Examples

ARRAY_LENGTH(expr)

Description

Arguments

Return Values

Example

ARRAY_MAX(expr)

Description

Arguments

Return Values

Example

ARRAY_MIN(expr)

Description

Arguments

Return Values

ARRAY_AGG(`expr`)

ARRAY_APPEND(`expr`, `val1`, `val2`, …)

ARRAY_AVG(`expr`)

ARRAY_BINARY_SEARCH(`expr`, `val`, …)

ARRAY_CONCAT(`expr1`, `expr2`, …)

ARRAY_CONTAINS(`expr`, `val`)

ARRAY_COUNT(`expr`)

ARRAY_DISTINCT(`expr`)

ARRAY_EXCEPT(`expr1`, `expr2`)

ARRAY_FLATTEN(`expr`, `depth`)

ARRAY_IFNULL(`expr`)

ARRAY_INSERT(`expr`, `pos`, `val1`, `val2`, …)

ARRAY_INTERSECT(`expr1`, `expr2`, ...)

ARRAY_LENGTH(`expr`)

ARRAY_MAX(`expr`)

ARRAY_MIN(`expr`)

ARRAY_MOVE(`expr`, `val1`, `val2`)

ARRAY_POSITION(`expr`, `val`)

ARRAY_PREPEND(`val1`, `val2`, … , `expr`)

ARRAY_PUT(`expr`, `val1`, `val2`, …)

ARRAY_RANGE(`start_num`, `end_num` `step_num` ])

ARRAY_REMOVE(`expr`, `val1`, `val2`, …)

ARRAY_REPEAT(`val`, `rep_int`)

ARRAY_REPLACE(`expr`, `val1`, `val2` [, `max_int`])

ARRAY_REPLACE_EQUIVALENT(`expr`, `val1`, `val2` [, `max_int`])

ARRAY_REVERSE(`expr`)

ARRAY_SORT(`expr`)

ARRAY_STAR(`expr`)

ARRAY_SUM(`expr`)

ARRAY_SYMDIFF(`expr1`, `expr2`, …)