Type Functions

reference

Type functions perform operations that check or convert expressions.

If any arguments to any of the following functions are MISSING then the result is also MISSING (i.e. no result is returned). Similarly, if any of the arguments passed to the functions are NULL or are of the wrong type (e.g. an integer instead of a string), then NULL is returned as the result.

ISARRAY(expression)

Description

Checks if the supplied expression is an array.

Arguments

expression: [Required] The expression to check.

Return Value

Returns True if expression is an array, otherwise returns MISSING, NULL or false.

Examples

SELECT ISARRAY(true) AS `boolean`,
       ISARRAY(MISSING) AS `missing`,
       ISARRAY(NULL) AS `null`,
       ISARRAY(123) AS `number`,
       ISARRAY("hello world") AS `string`,
       ISARRAY([1, 2, 3]) AS `array`,
       ISARRAY({"hello": "world"}) AS `object`;

[
  {
    "array": true,
    "boolean": false,
    "null": null,
    "number": false,
    "object": false,
    "string": false
  }
]

ISATOM(expression)

Description

Checks if the supplied expression is a Boolean, number, or string.

Arguments

expression: [Required] The expression to check.

Return Value

Returns True if expression is a Boolean, number, or string, otherwise returns MISSING, NULL or false.

Examples

SELECT ISATOM(true) AS `boolean`,
       ISATOM(MISSING) AS `missing`,
       ISATOM(NULL) AS `null`,
       ISATOM(123) AS `number`,
       ISATOM("hello world") AS `string`,
       ISATOM([1, 2, 3]) AS `array`,
       ISATOM({"hello": "world"}) AS `object`;

[
  {
    "array": false,
    "boolean": true,
    "null": null,
    "number": true,
    "object": false,
    "string": true
  }
]

ISBOOLEAN(expression)

Description

Checks if the supplied expression is a Boolean.

Arguments

expression: [Required] The expression to check.

Return Value

Returns True if expression is a Boolean, otherwise returns MISSING, NULL or false.

Examples

SELECT ISBOOLEAN(true) AS `boolean`,
       ISBOOLEAN(MISSING) AS `missing`,
       ISBOOLEAN(NULL) AS `null`,
       ISBOOLEAN(123) AS `number`,
       ISBOOLEAN("hello world") AS `string`,
       ISBOOLEAN([1, 2, 3]) AS `array`,
       ISBOOLEAN({"hello": "world"}) AS `object`;

[
  {
    "array": false,
    "boolean": true,
    "null": null,
    "number": false,
    "object": false,
    "string": false
  }
]

ISNUMBER(expression)

Description

Checks if the supplied expression is a number.

Arguments

expression: [Required] The expression to check.

Return Value

Returns True if expression is a number, otherwise returns MISSING, NULL or false.

Examples

SELECT ISNUMBER(true) AS `boolean`,
       ISNUMBER(MISSING) AS `missing`,
       ISNUMBER(NULL) AS `null`,
       ISNUMBER(123) AS `number`,
       ISNUMBER("hello world") AS `string`,
       ISNUMBER([1, 2, 3]) AS `array`,
       ISNUMBER({"hello": "world"}) AS `object`;

[
  {
    "array": false,
    "boolean": false,
    "null": null,
    "number": true,
    "object": false,
    "string": false
  }
]

ISOBJECT(expression)

Description

Checks if the supplied expression is an object.

Arguments

expression: [Required] The expression to check.

Return Value

Returns True if expression is an object, otherwise returns MISSING, NULL or false.

Examples

SELECT ISOBJECT(true) AS `boolean`,
       ISOBJECT(MISSING) AS `missing`,
       ISOBJECT(NULL) AS `null`,
       ISOBJECT(123) AS `number`,
       ISOBJECT("hello world") AS `string`,
       ISOBJECT([1, 2, 3]) AS `array`,
       ISOBJECT({"hello": "world"}) AS `object`;

[
  {
    "array": false,
    "boolean": false,
    "null": null,
    "number": false,
    "object": true,
    "string": false
  }
]

ISSTRING(expression)

Description

Checks if the supplied expression is a string.

Arguments

expression: [Required] The expression to check.

Return Value

Returns True if expression is a string, otherwise returns MISSING, NULL or false.

Examples

SELECT ISSTRING(true) AS `boolean`,
       ISSTRING(MISSING) AS `missing`,
       ISSTRING(NULL) AS `null`,
       ISSTRING(123) AS `number`,
       ISSTRING("hello world") AS `string`,
       ISSTRING([1, 2, 3]) AS `array`,
       ISSTRING({"hello": "world"}) AS `object`;

[
  {
    "array": false,
    "boolean": false,
    "null": null,
    "number": false,
    "object": false,
    "string": true
  }
]

ISVECTOR(`vector`, `dimension`, `format`)

Description

Checks if the supplied expression is an array of floating point numbers with the specified number of dimensions. This can be used to determine whether a field contains a vector value.

Arguments

vector: An array of floating point numbers, or any SQL++ expression that evaluates to an array of floating point numbers.
dimension: An integer representing the number of dimensions.
format: A string. This argument must always be present and must have the value "float32".

Return Value

Returns true if the expression is an array of floating point numbers with the specified number of dimensions.

Examples

To try the examples in this section, you must install the rgb and rgb-questions collections from the supplied vector sample, as described in Prerequisites.

ISVECTOR() Example 1

Query

SELECT ISVECTOR([1, 2, 3, 4], 4, "float32") as vector,
       ISVECTOR([1, 2, 3, 4], 3, "float32") as wrong_dimension,
       ISVECTOR(["a", "b", "c", "d"], 4, "float32") as wrong_values;

Results

[
  {
    "vector": true,
    "wrong_dimension": false,
    "wrong_values": false
  }
]

ISVECTOR() Example 2

Check whether the specified fields in the rgb collection contain vector values.

Query

SELECT ISVECTOR(description, 1, "float32") AS description,
       ISVECTOR(colorvect_l2, 3, "float32") AS colorvect_l2,
       ISVECTOR(embedding_vector_dot, 1536, "float32") AS embedding_vector_dot
FROM `vector-sample`.color.rgb LIMIT 1;

Results

[{
    "description": false,
    "colorvect_l2": true,
    "embedding_vector_dot": true
}]

The results show that the description field is not a vector field. The colorvect_l2 and embedding_vector_dot fields are vector fields, with the specified number of dimensions.

TYPE(expression)

Description

Checks the type of the supplied expression.

Arguments

expression: [Required] The expression to check.

Return Value

Returns one of the following strings, based on the value of expression:

"missing"
"null"
"boolean"
"number"
"string"
"array"
"object"
"binary"

Examples

SELECT TYPE(true) AS `boolean`,
       TYPE(MISSING) AS `missing`,
       TYPE(NULL) AS `null`,
       TYPE(123) AS `number`,
       TYPE("hello world") AS `string`,
       TYPE([1, 2, 3]) AS `array`,
       TYPE({"hello": "world"}) AS `object`;

[
  {
    "array": "array",
    "boolean": "boolean",
    "missing": "missing",
    "null": "null",
    "number": "number",
    "object": "object",
    "string": "string"
  }
]

TOARRAY(expression)

Description

Converts the supplied expression to an array.

Arguments

expression: [Required] The expression to convert.

Return Value

Returns one of the following strings, based on the value of expression:

Returns array as follows:

MISSING is MISSING.
NULL is NULL.
Arrays are themselves.
All other values are wrapped in an array.

Examples

SELECT TOARRAY(true) AS `boolean`,
       TOARRAY(MISSING) AS `missing`,
       TOARRAY(NULL) AS `null`,
       TOARRAY(123) AS `number`,
       TOARRAY("hello world") AS `string`,
       TOARRAY([1, 2, 3]) AS `array`,
       TOARRAY({"hello": "world"}) AS `object`;

[
  {
    "array": [
      1,
      2,
      3
    ],
    "boolean": [
      true
    ],
    "null": null,
    "number": [
      123
    ],
    "object": [
      {
        "hello": "world"
      }
    ],
    "string": [
      "hello world"
    ]
  }
]

TOATOM(expression)

Description

Converts the supplied expression to Boolean, number, or string.

Arguments

expression: [Required] The expression to convert.

Return Value

Returns atomic value as follows:

MISSING is MISSING.
NULL is NULL.
Arrays of length 1 are the result of TOATOM() on their single element.
Objects of length 1 are the result of TOATOM() on their single value.
Booleans, numbers, and strings are themselves.
All other values are NULL.

Examples

SELECT TOATOM(true) AS `boolean`,
       TOATOM(MISSING) AS `missing`,
       TOATOM(NULL) AS `null`,
       TOATOM(123) AS `number`,
       TOATOM("hello world") AS `string`,
       TOATOM([1, 2, 3]) AS `array`,
       TOATOM({"hello": "world"}) AS `object`;

[
  {
    "array": null,
    "boolean": true,
    "null": null,
    "number": 123,
    "object": "world",
    "string": "hello world"
  }
]

TOBOOLEAN(expression)

Description

Converts the supplied expression to a Boolean.

Arguments

expression: [Required] The expression to convert.

Return Value

Returns Boolean as follows:

MISSING is MISSING.
NULL is NULL.
False is false.
Numbers +0, -0, and NaN are false.
Empty strings, arrays, and objects are false.
All other values are true.

Examples

SELECT TOBOOLEAN(true) AS `boolean`,
       TOBOOLEAN(MISSING) AS `missing`,
       TOBOOLEAN(NULL) AS `null`,
       TOBOOLEAN(123) AS `number`,
       TOBOOLEAN("hello world") AS `string`,
       TOBOOLEAN([1, 2, 3]) AS `array`,
       TOBOOLEAN({"hello": "world"}) AS `object`;

[
  {
    "array": true,
    "boolean": true,
    "null": null,
    "number": true,
    "object": true,
    "string": true
  }
]

TONUMBER(expression [, string-expression])

Description

Converts the supplied expression to a number.

Arguments

expression: [Required] The expression to convert.
string-expression: [Optional] Characters to strip from the input expression before conversion, if the input expression is a string.

Return Value

Returns number as follows:

MISSING is MISSING.
NULL is NULL.
False is 0.
True is 1.
Numbers are themselves.
Strings that parse as numbers are those numbers.
All other values are NULL.

If string-expression is supplied, and the input expression is a string, then the following operations are carried out before conversion:

All whitespace is stripped from the input expression string.
All characters listed in string-expression are stripped from the input expression string.
If a decimal comma is detected, it is replaced with a decimal point — all other points must be removed from the input expression string.

If string-expression is not supplied, then the input expression string is parsed as-is.

Examples

SELECT TONUMBER(true) AS `boolean`,
       TONUMBER(MISSING) AS `missing`,
       TONUMBER(NULL) AS `null`,
       TONUMBER(123) AS `number`,
       TONUMBER("hello world") AS `string`,
       TONUMBER([1, 2, 3]) AS `array`,
       TONUMBER({"hello": "world"}) AS `object`;

[
  {
    "array": null,
    "boolean": 1,
    "null": null,
    "number": 123,
    "object": null,
    "string": null
  }
]

SELECT TONUMBER("AU$123456.78", "AU$") AS `aud`,
       TONUMBER("€123.456,78   ", "€.") AS `eur`,
       TONUMBER("$   123,456.78", "$,") AS `usd`,
       TONUMBER("¥123 456 789.00", "¥") AS `yen`;

[
  {
    "aud": 123456.78,
    "eur": 123456.78,
    "usd": 123456.78,
    "yen": 123456789
  }
]

TOOBJECT(expression)

Description

Converts the supplied expression to an object.

Arguments

expression: [Required] The expression to convert.

Return Value

Returns object as follows:

MISSING is MISSING.
NULL is NULL.
Objects are themselves.
All other values are the empty object.

Examples

SELECT TOOBJECT(true) AS `boolean`,
       TOOBJECT(MISSING) AS `missing`,
       TOOBJECT(NULL) AS `null`,
       TOOBJECT(123) AS `number`,
       TOOBJECT("hello world") AS `string`,
       TOOBJECT([1, 2, 3]) AS `array`,
       TOOBJECT({"hello": "world"}) AS `object`;

[
  {
    "array": {},
    "boolean": {},
    "null": null,
    "number": {},
    "object": {
      "hello": "world"
    },
    "string": {}
  }
]

TOSTRING(expression)

Description

Converts the supplied expression to a string.

Arguments

expression: [Required] The expression to convert.

Return Value

Returns string as follows:

MISSING is MISSING.
NULL is NULL.
False is "false".
True is "true".
Numbers are their string representation.
Strings are themselves.
All other values are NULL.

Examples

SELECT TOSTRING(true) AS `boolean`,
       TOSTRING(MISSING) AS `missing`,
       TOSTRING(NULL) AS `null`,
       TOSTRING(123) AS `number`,
       TOSTRING("hello world") AS `string`,
       TOSTRING([1, 2, 3]) AS `array`,
       TOSTRING({"hello": "world"}) AS `object`;

[
  {
    "array": null,
    "boolean": "true",
    "null": null,
    "number": "123",
    "object": null,
    "string": "hello world"
  }
]

Type Functions

ISARRAY(expression)

Description

Arguments

Return Value

Examples

ISATOM(expression)

Description

Arguments

Return Value

Examples

ISBOOLEAN(expression)

Description

Arguments

Return Value

Examples

ISNUMBER(expression)

Description

Arguments

Return Value

Examples

ISOBJECT(expression)

Description

Arguments

Return Value

Examples

ISSTRING(expression)

Description

Arguments

Return Value

Examples

ISVECTOR(vector, dimension, format)

Description

Arguments

Return Value

Examples

TYPE(expression)

Description

Arguments

Return Value

Examples

TOARRAY(expression)

Description

Arguments

Return Value

Examples

TOATOM(expression)

Description

Arguments

Return Value

Examples

TOBOOLEAN(expression)

Description

Arguments

Return Value

Examples

TONUMBER(expression [, string-expression])

Description

Arguments

Return Value

Examples

TOOBJECT(expression)

Description

Arguments

Return Value

Examples

TOSTRING(expression)

Description

Arguments

Return Value

Examples

ISVECTOR(`vector`, `dimension`, `format`)