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String Functions

concept

March 23, 2025

+ 12

String functions perform operations on a string input value and returns a string or other value.

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.

CONCAT(`string1`, `string2`, …)

Description

This function takes two or more strings and returns a new string after concatenating the input strings. If there are fewer than two arguments, then it returns an error.

Arguments

string1, string2, ...: [At least 2 are required] The strings, or valid expressions which evaluate to strings, to be concatenated together.

Return Value

A new string, concatenated from the input strings.

Examples

n1ql
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SELECT CONCAT("abc", "def", "ghi") AS concat;

json
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[
  {
    "concat": "abcdefghi"
  }
]

CONCAT2(`separator`, `arg1`, `arg2`, …)

Description

This function takes the input strings, or arrays of strings, and concatenates them with the specified separator between each input string. If there are fewer than two arguments, then it returns an error.

Arguments

separator: [Required] The string to separate the input strings. If no separator is required, specify the empty string "".
arg1, arg2, ...: [At least 1 is required] The strings, or arrays of strings, to be concatenated together.

Return Value

A new string, concatenated from the inputs, with the separator between each input. Arrays of strings are flattened and concatenated in the same order. If there is only one string argument, the separator is not used.

If any argument or array element is MISSING, returns MISSING. If any argument or array element is non-string, returns NULL.

Examples

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SELECT CONCAT2('-','a','b',['c','d'],['xyz']) AS c1,
CONCAT2('-','a') AS c2,
CONCAT2('-',['b']) AS c3;

json
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[
  {
    "c1": "a-b-c-d-xyz",
    "c2": "a",
    "c3": "b"
  }
]

CONTAINS(in_str, search_str)

Description

Checks whether or not the specified search string is a substring of the input string (i.e. exists within). This returns true if the substring exists within the input string, otherwise false is returned.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to search within.
search_str: A string, or any valid expression which evaluates to a string, that is the string to search for.

Return Value

A boolean, representing whether the search string exists within the input string.

Examples

n1ql
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SELECT CONTAINS("N1QL is awesome", "N1QL") as n1ql,
       CONTAINS("N1QL is awesome", "SQL") as no_sql;

json
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{
    "results": [
        {
            "n1ql": true,
            "no_sql": false
        }
    ]
}

INITCAP(in_str)

Description

Converts the string so that the first letter of each word is uppercase and every other letter is lowercase (known as 'Title Case').

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to convert to title case.

Return Value

A string, representing the input string converted to title case.

Limitations

This function capitalizes the initial letter of every word in the sentence, this means that even short words such as "the" and "or" will be capitalized. This does not strictly follow title case conventions used in the writing domain.

Examples

n1ql
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SELECT INITCAP("N1QL is awesome") as n1ql;

json
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{
    "results": [
        {
            "n1ql": "N1ql Is Awesome"
        }
    ]
}

LENGTH(in_str)

Description

Finds the length of a string, the length is defined as the number of characters within the string.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to find the length of.

Return Value

An integer representing the length of the string.

Examples

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SELECT LENGTH("") as empty_string,
LENGTH("N1QL is awesome") as n1ql;

json
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{
    "results": [
        {
            "empty_string": 0,
            "n1ql": 15
        }
    ]
}

LOWER(in_str)

Description

Converts all characters in the input string to lower case. This is useful for canonical comparison of string values.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to convert to lower case.

Return Value

A string representing the input string converted to lower case.

Examples

n1ql
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SELECT LOWER("N1QL is awesome") as n1ql;

json
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{
    "results": [
        {
            "n1ql": "n1ql is awesome"
        }
    ]
}

LTRIM(in_str [, char])

Description

Removes all leading characters from a string. The function removes all consecutive characters from the beginning of the string that match the specified characters and stops when it encounters a character that does not match any of the specified characters.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to remove the leading characters from.
char: [Optional; default is whitespace, i.e. " "]

A string, or any valid expression which evaluates to a string, that represents the characters to trim from the input string. Each character in this string will be trimmed from the input string, it is therefore not necessary to delimit the characters to trim. For example, specifying a character value of "abc" will trim the characters "a", "b" and "c" from the start of the string.

Return Value

A string representing the input string with leading characters removed.

Examples

n1ql
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SELECT LTRIM("...N1QL is awesome", ".") as dots,
       LTRIM("     N1QL is awesome", " ") as explicit_spaces,
       LTRIM("     N1QL is awesome") as implicit_spaces,
       LTRIM("N1QL is awesome") as no_dots;

json
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{
    "results": [
        {
            "dots": "N1QL is awesome",
            "explicit_spaces": "N1QL is awesome",
            "implicit_spaces": "N1QL is awesome",
            "no_dots": "N1QL is awesome"
        }
    ]
}

POSITION(in_str, search_str)

Description

Finds the first position of the search string within the string, this position is zero-based, i.e., the first position is 0. If the search string does not exist within the input string then the function returns -1.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to search within.
search_str: A string, or any valid expression which evaluates to a string, that is the string to search for.

Return Value

An integer representing the first position of the search string.

Examples

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SELECT POSITION("N1QL is awesome", "awesome") as awesome,
       POSITION("N1QL is awesome", "N1QL") as n1ql,
       POSITION("N1QL is awesome", "SQL") as sql

json
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{
    "results": [
        {
            "awesome": 8,
            "n1ql": 0,
            "sql": -1
        }
    ]
}

REPEAT(in_str, n)

Description

Creates a new string which is the input string repeated the specified number of times.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to repeat.
n: An integer, or any valid expression which evaluates to an integer, that is the number of times to repeat the string.

Return Value

A string representing the string generated by repeating the input string.

Limitations

It is possible to generate very large strings using this function. In some cases the query engine may be unable to process all of these and cause excessive resource consumption. It is therefore recommended that you first validate the inputs to this function to ensure that the generated result is a reasonable size.

Examples

n1ql
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SELECT REPEAT("N1QL", 0) as empty_string,
       REPEAT("N1QL", 3) as n1ql_3;

json
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{
    "results": [
        {
            "empty_string": "",
            "n1ql_3": "N1QLN1QLN1QL"
        }
    ]
}

REPLACE(in_str, search_str, replace [, n ])

Description

Replaces occurrences of a given substring in an input string.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to search for replacements in.
search_str: A string, or any valid expression which evaluates to a string, that is the string to replace.
replace: A string, or any valid expression which evaluates to a string, that is the string to replace the search string with.
n: [Optional; default is all instances of the search string are replaced]

An integer, or any valid expression which evaluates to an integer, which represents the number of instances of the search string to replace. If a negative value is specified then all instances of the search string are replaced.

Return Value

A string representing the input string with the specified substring replaced.

Examples

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SELECT REPLACE("SQL SQL SQL", "S", "N1", -2) as negative_n,
       REPLACE("SQL SQL SQL", "S", "N1", 2) as replace_2,
       REPLACE("SQL SQL SQL", "S", "N1") as replace_all;

json
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{
    "results": [
        {
            "negative_n": "N1QL N1QL N1QL",
            "replace_2": "N1QL N1QL SQL",
            "replace_all": "N1QL N1QL N1QL"
        }
    ]
}

REVERSE(in_str)

Description

Reverses the order of the characters in a given string. i.e. The first character becomes the last character and the last character becomes the first character etc. This is useful for testing whether or not a string is a palindrome.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to reverse.

Return Value

A string representing the input string with its characters reversed.

Examples

n1ql
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SELECT REVERSE("N1QL is awesome") as n1ql,
       REVERSE("racecar") as palindrome;

json
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{
    "results": [
        {
            "n1ql": "emosewa si LQ1N",
            "palindrome": "racecar"
        }
    ]
}

RTRIM(in_str [, char])

Description

Removes all trailing characters from a string. The function removes all consecutive characters from the end of the string that match the specified characters and stops when it encounters a character that does not match any of the specified characters.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to convert to remove trailing characters from.
char: [Optional; default is whitespace, i.e. " "]

A string, or any valid expression which evaluates to a string, that represents the characters to trim from the input string. Each character in this string will be trimmed from the input string, it is therefore not necessary to delimit the characters to trim. For example specifying a character value of "abc" will trim the characters "a", "b" and "c" from the start of the string.

Return Value

A string representing the input string with its trailing characters removed.

Examples

n1ql
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SELECT RTRIM("N1QL is awesome...", ".") as dots,
       RTRIM("N1QL is awesome     ", " ") as explicit_spaces,
       RTRIM("N1QL is awesome     ") as implicit_spaces,
       RTRIM("N1QL is awesome") as no_dots;

json
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{
    "results": [
        {
            "dots": "N1QL is awesome",
            "explicit_spaces": "N1QL is awesome",
            "implicit_spaces": "N1QL is awesome",
            "no_dots": "N1QL is awesome"
        }
    ]
}

SPLIT(in_str [, in_substr])

Description

Splits the string into an array of substrings, based on the specified separator string.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to split.
in_substr: A string, or any valid expression which evaluates to a string, that is the substring to split the input string on.

Return Value

An array of strings containing the strings created by splitting the input string.

Examples

n1ql
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SELECT SPLIT("N1QL is awesome", " ") as explicit_spaces,
       SPLIT("N1QL is awesome") as implicit_spaces,
       SPLIT("N1QL is awesome", "is") as split_is

json
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{
    "results": [
        {
            "explicit_spaces": [
                "N1QL",
                "is",
                "awesome"
            ],
            "implicit_spaces": [
                "N1QL",
                "is",
                "awesome"
            ],
            "split_is": [
                "N1QL ",
                " awesome"
            ]
        }
    ]
}

SUBSTR(in_str, start_pos [, length])

Description

Returns the substring (of given length) starting at the provided position. The position is zero-based, i.e. the first position is 0. If position is negative, it is counted from the end of the string; -1 is the last position in the string.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to convert to extract the substring from.
start_pos: An integer, or any valid expression which evaluates to an integer, that is the start position of the substring.
length: [Optional; default is to capture to the end of the string]

An integer, or any valid expression which evaluates to an integer, that is the length of the substring to extract.

Return Value

A string representing the substring extracted from the input string.

Examples

n1ql
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SELECT SUBSTR("N1QL is awesome", 3) as end_of_string,
       SUBSTR("N1QL is awesome", 3, 1) as single_letter,
       SUBSTR("N1QL is awesome", 3, 3) as three_letters

json
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{
    "results": [
        {
            "end_of_string": "L is awesome",
            "single_letter": "L",
            "three_letters": "L i"
        }
    ]
}

SUFFIXES(in_str)

Description

Generates an array of all the suffixes of the input string.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to generate the suffixes of.

Return Value

An array of strings containing all of the suffixes of the input string.

Examples

n1ql
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SELECT SUFFIXES("N1QL is awesome") as n1ql

json
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{
    "results": [
        {
            "n1ql": [
                "N1QL is awesome",
                "1QL is awesome",
                "QL is awesome",
                "L is awesome",
                " is awesome",
                "is awesome",
                "s awesome",
                " awesome",
                "awesome",
                "wesome",
                "esome",
                "some",
                "ome",
                "me",
                "e"
            ]
        }
    ]
}

The following example uses the SUFFIXES() function to index and query the airport names when a partial airport name is given.

n1ql
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CREATE INDEX autocomplete_airport_name
ON `travel-sample`.inventory.airport ( DISTINCT ARRAY array_element FOR array_element
IN SUFFIXES(LOWER(airportname)) END )

n1ql
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SELECT airportname
FROM `travel-sample`.inventory.airport
WHERE ANY array_element
IN SUFFIXES(LOWER(airportname)) SATISFIES array_element LIKE 'washing%' END

json
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{
    "results": [
        {
            "airportname": "Ronald Reagan Washington Natl"
        },
        {
            "airportname": "Washington Dulles Intl"
        },
        {
            "airportname": "Baltimore Washington Intl"
        },
        {
            "airportname": "Washington Union Station"
        }
    ]
}

This blog provides more information about this example.

TITLE(in_str)

Alias for INITCAP().

TOKENS(in_str, opt)

Description

This function tokenizes (i.e. breaks up into meaningful segments) the given input string based on specified delimiters, and other options. It recursively enumerates all tokens in a JSON value and returns an array of values (JSON atomic values) as the result.

Arguments

in_str

A valid JSON object, this can be anything: constant literal, simple JSON value, JSON key name or the whole document itself.

The following table lists the rules for each JSON type:

JSON Type	Return Value
MISSING	[]
NULL	[NULL]
false	[false]
true	[true]
number	[number]
string	SPLIT(string)
array	FLATTEN(TOKENS(element) for each element in array (Concatenation of element tokens)
object	For each name-value pair, name+TOKENS(value)

JSON Type

Return Value

MISSING

[]

NULL

[NULL]

false

[false]

true

[true]

number

[number]

string

SPLIT(string)

array

FLATTEN(TOKENS(element) for each element in array

(Concatenation of element tokens)

object

For each name-value pair, name+TOKENS(value)

opt

A JSON object indicating the options passed to the TOKENS() function. Options can take the following options, and each invocation of TOKENS() can choose one or more of the options:

{"name": true}

Optional. Valid values are true or false. By default, this is set to true and TOKENS() will include field names. You can choose to not include field names by setting this option to false.

{"case":"lower"}

Optional. Valid values are lower or upper. Default is neither, as in it returns the case of the original data. Use this option to specify the case sensitivity.

{"specials": true}

Optional. Use this option to preserve strings with specials characters, such as email addresses, URLs, and hyphenated phone numbers. The default value is false.

The specials options preserves special characters except at the end of a word.

Return Value

An array of strings containing all of the tokens obtained from the input string.

Examples

By default, for speed, the results are randomly ordered. To make the difference more clear between the first two example queries, the ARRAY_SORT() function is used.

Example 1. List the tokens of an array where specials is FALSE

n1ql
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SELECT ARRAY_SORT( TOKENS( ['jim@example.com, kim@example.com, http://example.com/, 408-555-1212'],
                 { 'specials': false }));

json
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[
  {
    "$1": [
      "1212",
      "408",
      "555",
      "abc",
      "com",
      "http",
      "jim",
      "kim"
    ]
  }
]

Example 2. List the tokens of an array where specials is TRUE

n1ql
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SELECT ARRAY_SORT( TOKENS(['jim@example.com, kim@example.com, http://example.com/, 408-555-1212'],
                 { 'specials': true }));

json
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[
  {
    "$1": [
      "1212",
      "408",
      "408-555-1212",
      "555",
      "abc",
      "com",
      "http",
      "http://example.com",
      "jim",
      "jim@example.com",
      "kim",
      "kim@example.com"
    ]
  }
]

Example 3. Convert all of the URL data into UPPER case and adds the full URL to the delimited words

n1ql
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SELECT ARRAY_SORT( TOKENS(url) ) AS defaulttoken,
       ARRAY_SORT( TOKENS(url, {"specials":true, "case":"UPPER"}) ) AS specialtoken
FROM `travel-sample` WHERE type = 'hotel'
LIMIT 1;

json
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[
  {
    "defaulttoken": [
      "http",
      "org",
      "uk",
      "www",
      "yha"
    ],
    "specialtoken": [
      "HTTP",
      "HTTP://WWW.YHA.ORG.UK",
      "ORG",
      "UK",
      "WWW",
      "YHA"
    ]
  }
]

You can also use {"case":"lower"} or {"case":"upper"} to have case sensitive search. Index creation and querying can use this and other parameters in combination. These parameters should be passed within the query predicates as well. The parameters and values must match exactly for N1QL to pick up and use the index correctly.

Example 4. Create an index with case and use it your application

n1ql
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CREATE INDEX idx_url_upper_special on `travel-sample`(
    DISTINCT ARRAY v for v in
        tokens(url, {"specials":true, "case":"UPPER"})
    END ) where type = 'hotel';

n1ql
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SELECT name, address, url
FROM `travel-sample`
WHERE ANY  v in tokens(url, {"specials":true, "case":"UPPER"})
      SATISFIES v = "HTTP://WWW.YHA.ORG.UK"
      END
AND type = 'hotel' ;

json
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{
    "results": [
        {
            "address": "Capstone Road, ME7 3JE",
            "name": "Medway Youth Hostel",
            "url": "http://www.yha.org.uk"
        }
    ]
}

TRIM(in_str [, char])

Description

Removes all leading and trailing characters from a string. The function removes all consecutive characters from the beginning and end of the string that match the specified characters and stops when it encounters a character that does not match any of the specified characters. This function is equivalent to calling LTRIM() and RTRIM() successively.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to convert to remove trailing and leading characters from.
char: [Optional; default is whitespace, i.e. " "]

A string, or any valid expression which evaluates to a string, that represents the characters to trim from the input string. Each character in this string will be trimmed from the input string, it is therefore not necessary to delimit the characters to trim. For example specifying a character value of "abc" will trim the characters "a", "b" and "c" from the start of the string.

Return Value

A string representing the input string with trailing and leading characters removed.

Examples

n1ql
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SELECT TRIM("...N1QL is awesome...", ".") as dots,
       TRIM("     N1QL is awesome     ", " ") as explicit_spaces,
       TRIM("     N1QL is awesome     ") as implicit_spaces,
       TRIM("N1QL is awesome") as no_dots;

json
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{
    "results": [
        {
            "dots": "N1QL is awesome",
            "explicit_spaces": "N1QL is awesome",
            "implicit_spaces": "N1QL is awesome",
            "no_dots": "N1QL is awesome"
        }
    ]
}

UPPER(in_str)

Description

Converts all characters in the input string to upper case.

Arguments

in_str: A string, or any valid expression which evaluates to a string, that is the string to convert to upper case.

Return Value

A string representing the input string converted to upper case.

Examples

n1ql
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SELECT UPPER("N1QL is awesome") as n1ql;

json
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{
    "results": [
        {
            "n1ql": "N1QL IS AWESOME"
        }
    ]
}

String Functions

CONCAT(string1, string2, …)

Description

Arguments

Return Value

Examples

CONCAT2(separator, arg1, arg2, …)

Description

Arguments

Return Value

Examples

CONTAINS(in_str, search_str)

Description

Arguments

Return Value

Examples

INITCAP(in_str)

Description

Arguments

Return Value

Limitations

Examples

LENGTH(in_str)

Description

Arguments

Return Value

Examples

LOWER(in_str)

Description

Arguments

Return Value

Examples

LTRIM(in_str [, char])

Description

Arguments

Return Value

Examples

POSITION(in_str, search_str)

Description

Arguments

Return Value

Examples

REPEAT(in_str, n)

Description

Arguments

Return Value

Limitations

Examples

REPLACE(in_str, search_str, replace [, n ])

Description

Arguments

Return Value

Examples

REVERSE(in_str)

Description

Arguments

Return Value

Examples

RTRIM(in_str [, char])

Description

Arguments

Return Value

Examples

SPLIT(in_str [, in_substr])

Description

Arguments

Return Value

Examples

SUBSTR(in_str, start_pos [, length])

Description

Arguments

Return Value

Examples

SUFFIXES(in_str)

Description

Arguments

Return Value

Examples

TITLE(in_str)

TOKENS(in_str, opt)

CONCAT(`string1`, `string2`, …)

CONCAT2(`separator`, `arg1`, `arg2`, …)