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String Functions

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    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.

    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
    SELECT CONTAINS("N1QL is awesome", "N1QL") as n1ql,
           CONTAINS("N1QL is awesome", "SQL") as no_sql;
    
    {
        "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
    SELECT INITCAP("N1QL is awesome") as n1ql;
    
    {
        "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
    SELECT LENGTH("") as empty_string,
    LENGTH("N1QL is awesome") as n1ql;
    
    {
        "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
    SELECT LOWER("N1QL is awesome") as n1ql;
    
    {
        "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
    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;
    
    {
        "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
    SELECT POSITION("N1QL is awesome", "awesome") as awesome,
           POSITION("N1QL is awesome", "N1QL") as n1ql,
           POSITION("N1QL is awesome", "SQL") as sql
    
    {
        "results": [
            {
                "awesome": 8,
                "n1ql": 0,
                "sql": -1
            }
        ]
    }

    Returns

    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
    SELECT REPEAT("N1QL", 0) as empty_string,
           REPEAT("N1QL", 3) as n1ql_3;
    
    {
        "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
    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;
    
    {
        "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
    SELECT REVERSE("N1QL is awesome") as n1ql,
           REVERSE("racecar") as palindrome;
    
    {
        "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
    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;
    
    {
        "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
    SELECT SPLIT("N1QL is awesome", " ") as explicit_spaces,
           SPLIT("N1QL is awesome") as implicit_spaces,
           SPLIT("N1QL is awesome", "is") as split_is
    
    {
        "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
    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
    
    {
        "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
    SELECT SUFFIXES("N1QL is awesome") as n1ql
    
    {
        "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.

    CREATE INDEX autocomplete_airport_name
    ON `travel-sample`( DISTINCT ARRAY array_element FOR array_element
    IN SUFFIXES(LOWER(airportname)) END )
    WHERE type = "airport";
    SELECT airportname
    FROM `travel-sample`
    WHERE ANY array_element
    IN SUFFIXES(LOWER(airportname)) SATISFIES array_element LIKE 'washing%' END
    AND type="airport";
    {
        "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)

    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.

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

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

    SELECT ARRAY_SORT( TOKENS( ['jim@abc.com, kim@abc.com, http://abc.com/, 408-555-1212'],
                     { 'specials': false });
    
    Results:
    [
      {
        "$1": [
          "1212",
          "408",
          "555",
          "abc",
          "com",
          "http",
          "jim",
          "kim"
        ]
      }
    ]

    Example 1b: List the tokens of an array where specials is TRUE.

    SELECT ARRAY_SORT( TOKENS(['jim@abc.com, kim@abc.com, http://abc.com/, 408-555-1212'],
    	           { 'specials': true }));
    
    Results:
    [
      {
        "$1": [
          "1212",
          "408",
          "408-555-1212",
          "555",
          "abc",
          "com",
          "http",
          "http://abc.com",
          "jim",
          "jim@abc.com",
          "kim",
          "kim@abc.com"
        ]
      }
    ]

    Example 2: Convert all of the URL data into UPPER case and adds the full URL to the delimited words.

    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;
    
    [
      {
        "defaulttoken": [
          "co",
          "http",
          "tantallonhouse",
          "uk",
          "www"
        ],
        "specialtoken": [
          "CO",
          "HTTP",
          "HTTP://WWW.TANTALLONHOUSE.CO.UK",
          "TANTALLONHOUSE",
          "UK",
          "WWW"
        ]
      }
    ]

    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 3: Create an index with case and use it your application.

    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';
    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' ;
    
    {
        "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
    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;
    
    {
        "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
    SELECT UPPER("N1QL is awesome") as n1ql;
    
    {
        "results": [
            {
                "n1ql": "N1QL IS AWESOME"
            }
        ]
    }