String Functions
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.
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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, otherwisefalse
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 ofTOKENS()
can choose one or more of the options:-
{"name": true}: Optional. Valid values are
true
orfalse
. By default, this is set to true andTOKENS()
will include field names. You can choose to not include field names by setting this option tofalse
. -
{"case":"lower"}: Optional. Valid values are
lower
orupper
. 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()
andRTRIM()
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" } ] }