Scalar functions
Numeric functions¶
ABS
¶
Since: -
1 |
|
The absolute value of a value.
AS_VALUE
¶
Since: 0.9.0
1 |
|
Creates a copy of a key column in the value.
For example:
1 2 3 4 5 6 7 |
|
CAST
¶
Since: -
1 |
|
Converts one type to another. The following casts are supported:
from | to | notes |
---|---|---|
any | STRING |
Converts the type to its string representation. |
VARCHAR |
BOOLEAN |
Any string that exactly matches true , case-insensitive, is converted to true . Any other value is converted to false . |
VARCHAR |
INT , BIGINT , DECIMAL , DOUBLE |
Converts string representation of numbers to number types. Conversion will fail if text does not contain a number or the number does not fit in the indicated type. |
INT , BIGINT , DECIMAL , DOUBLE |
INT , BIGINT , DECIMAL , DOUBLE |
Convert between numeric types. Conversion can result in rounding |
ARRAY |
ARRAY |
(Since 0.14) Convert between arrays of different element types |
MAP |
MAP |
(Since 0.14) Convert between maps of different key and value types |
STRUCT |
STRUCT |
(Since 0.14) Convert between structs of different field types. Only fields that exist in the target STRUCT type are copied across. Any fields in the target type that don't exist in the source are set to NULL . Field name matching is case-sensitive. |
CEIL
¶
Since: -
1 |
|
The ceiling of a value.
ENTRIES
¶
Since: 0.6.0
1 |
|
Constructs an array of structs from the entries in a map. Each struct has
a field named K
containing the key, which is a string, and a field named
V
, which holds the value.
If sorted
is true, the entries are sorted by key.
EXP
¶
Since: 0.6.0
1 |
|
The exponential of a value.
FLOOR
¶
Since: -
1 |
|
The floor of a value.
GENERATE_SERIES
¶
Since: 0.6.0
1 |
|
1 |
|
Constructs an array of values between start
and end
(inclusive).
Parameters start
and end
can be an INT
or BIGINT
.
step
, if supplied, specifies the step size. The step can be positive or negative.
If not supplied, step
defaults to 1
. Parameter step
must be an INT
.
GEO_DISTANCE
¶
Since: 0.6.0
1 |
|
The great-circle distance between two lat-long points, both specified
in decimal degrees. An optional final parameter specifies KM
(the default) or miles
.
LN
¶
Since: 0.6.0
1 |
|
The natural logarithm of a value.
RANDOM
¶
Since: -
1 |
|
Return a random DOUBLE value between 0.0 and 1.0.
ROUND
¶
Since: 0.6.0
1 |
|
1 |
|
Round a value to the number of decimal places as specified by scale to the right of the decimal point. If scale is negative then value is rounded to the right of the decimal point.
Numbers equidistant to the nearest value are rounded up (in the positive direction). If the number of decimal places is not provided it defaults to zero.
SIGN
¶
Since: 0.6.0
1 |
|
The sign of a numeric value as an INTEGER:
- -1 if the argument is negative
- 0 if the argument is zero
- 1 if the argument is positive
null
argument is null
SQRT
¶
Since: 0.6.0
1 |
|
The square root of a value.
Collections¶
ARRAY
¶
Since: 0.7.0
1 |
|
Construct an array from a variable number of inputs.
ARRAY_CONTAINS
¶
Since: 0.6.0
1 |
|
Given an array, checks if a search value is contained in the array.
Accepts any ARRAY
type. The type of the second param must match the element type of the ARRAY
.
ARRAY_DISTINCT
¶
Since: 0.10.0
1 |
|
Returns an array of all the distinct values, including NULL if present, from the input array. The output array elements are in order of their first occurrence in the input.
Returns NULL if the input array is NULL.
Examples:
1 2 |
|
ARRAY_EXCEPT
¶
Since: 0.10.0
1 |
|
Returns an array of all the distinct elements from an array, except for those also present in a second array. The order of entries in the first array is preserved but duplicates are removed.
Returns NULL if either input is NULL.
Examples:
1 2 |
|
ARRAY_INTERSECT
¶
Since: 0.10.0
1 |
|
Returns an array of all the distinct elements from the intersection of both input arrays. The order of entries in the output is the same as in the first input array.
Returns NULL if either input array is NULL.
Examples:
1 2 |
|
ARRAY_JOIN
¶
Since: 0.10.0
1 |
|
Creates a flat string representation of all the elements contained in the given array.
The elements in the resulting string are separated by the chosen delimiter
,
which is an optional parameter that falls back to a comma ,
. The current implementation only
allows for array elements of primitive ksqlDB types.
ARRAY_LENGTH
¶
Since: 0.8.0
1 |
|
Given an array, return the number of elements in the array.
If the supplied parameter is NULL the method returns NULL.
ARRAY_MAX
¶
Since: 0.10.0
1 |
|
Returns the maximum value from within a given array of primitive elements (not arrays of other arrays, or maps, or structs, or combinations thereof).
Array entries are compared according to their natural sort order, which sorts the various data-types per the following examples:
- array_max[-1, 2, NULL, 0] -> 2
- array_max[false, NULL, true] -> true
- array_max['Foo', 'Bar', NULL, 'baz'] -> 'baz'
(lower-case characters are "greater" than upper-case characters)
If the array field is NULL, or contains only NULLs, then NULL is returned.
ARRAY_MIN
¶
Since: 0.10.0
1 |
|
Returns the minimum value from within a given array of primitive elements (not arrays of other arrays, or maps, or structs, or combinations thereof).
Array entries are compared according to their natural sort order, which sorts the various data-types per the following examples:
- array_min[-1, 2, NULL, 0] -> -1
- array_min[false, NULL, true] -> false
- array_min['Foo', 'Bar', NULL, 'baz'] -> 'Bar'
If the array field is NULL, or contains only NULLs, then NULL is returned.
ARRAY_REMOVE
¶
Since: 0.11.0
1 |
|
Removes all elements from the input array equal to element
.
Examples:
1 2 3 |
|
If the array field is NULL then NULL is returned.
ARRAY_SORT
¶
Since: 0.10.0
1 |
|
Given an array of primitive elements (not arrays of other arrays, or maps, or structs, or combinations thereof), returns an array of the same elements sorted according to their natural sort order. Any NULLs contained in the array will always be moved to the end.
For example:
- array_sort[-1, 2, NULL, 0] -> [-1, 0, 2, NULL]
- array_sort[false, NULL, true] -> [false, true, NULL]
- array_sort['Foo', 'Bar', NULL, 'baz'] -> ['Bar', 'Foo', 'baz', NULL]
If the array field is NULL then NULL is returned.
An optional second parameter can be used to specify whether to sort the elements in 'ASC'ending or 'DESC'ending order. If neither is specified then the default is ascending order.
ARRAY_UNION
¶
Since: 0.10.0
1 |
|
Returns an array of all the distinct elements from both input arrays, in the order in which they are first encountered.
Returns NULL if either input array is NULL.
Examples:
1 2 |
|
AS_MAP
¶
Since: 0.6.0
1 |
|
Construct a map from a list of keys and a list of values.
ELT
¶
Since: 0.6.0
1 |
|
Returns element n
in the args
list of strings, or NULL if n
is less than
1 or greater than the number of arguments. This function is 1-indexed. ELT is
the complement to FIELD.
FIELD
¶
Since: 0.6.0
1 |
|
Returns the 1-indexed position of str
in args
, or 0 if not found.
If str
is NULL, the return value is 0, because NULL is not considered
to be equal to any value. FIELD is the complement to ELT.
JSON_ARRAY_CONTAINS
¶
Since: 0.6.0
1 |
|
Given a STRING
containing a JSON array, checks if a search value is contained in the array.
Returns false
if the first parameter does not contain a JSON array.
MAP
¶
Since: 0.7.0
1 |
|
Construct a map from specific key-value tuples.
MAP_KEYS
¶
Since: 0.10.0
1 |
|
Returns an array that contains all of the keys from the specified map.
Returns NULL if the input map is NULL.
Example:
1 |
|
MAP_VALUES
¶
Since: 0.10.0
1 |
|
Returns an array that contains all of the values from the specified map.
Returns NULL if the input map is NULL.
Example:
1 |
|
MAP_UNION
¶
Since: 0.10.0
1 |
|
Returns a new map containing the union of all entries from both input maps. If a key is present in both input maps, the corresponding value from map2 is returned.
Returns NULL if all of the input maps are NULL.
Example:
1 2 3 |
|
SLICE
¶
Since: 0.6.0
1 |
|
Slices a list based on the supplied indices. The indices start at 1 and include both endpoints.
Strings¶
CHR
¶
Since: 0.10.0
1 |
|
Returns a single-character string representing the Unicode code-point described by the input. The input parameter can be either a decimal character code or a string representation of a UTF code.
Returns NULL if the input is NULL or does not represent a valid code-point.
Commonly used to insert control characters such as Tab
(9), Line Feed
(10), or Carriage Return
(13) into strings.
Examples:
1 2 3 4 |
|
CONCAT
¶
Since: -
1 |
|
Concatenate two or more string expressions. Any input strings which evaluate to NULL are replaced with empty string in the output.
CONCAT_WS
¶
Since: 0.10.0
1 |
|
Concatenates two or more string expressions, inserting a separator string between each.
If the separator is NULL, this function returns NULL. Any expressions which evaluate to NULL are skipped.
Example:
1 |
|
ENCODE
¶
Since: 0.10.0
1 |
|
Given a STRING that is encoded as input_encoding
, encode it using the output_encoding
. The accepted input and output encodings are:
hex
, utf8
, ascii
, and base64
. Throws an exception if the provided encodings are not supported.
For example, to encode a string in hex
to utf8
, use ENCODE(string, 'hex', 'utf8')
.
EXTRACTJSONFIELD
¶
Since: -
1 |
|
Given a STRING that contains JSON data, extract the value at the specified JSONPath.
For example, given a STRING containing the following JSON:
1 2 3 4 5 6 7 |
|
EXTRACTJSONFIELD(message, '$.log.cloud')
returns the STRING gcp836Csd
.
If the requested JSONPath does not exist, the function returns NULL.
The result of EXTRACTJSONFIELD is always a STRING. Use CAST
to convert the result to another
type. For example, CAST(EXTRACTJSONFIELD(message, '$.log.instance') AS INT)
will extract the
instance number from the above JSON object as a INT.
Note
EXTRACTJSONFIELD is useful for extracting data from JSON where either the schema of the JSON data is not static, or where the JSON data is embedded in a row encoded using a different format, for example, a JSON field within an Avro-encoded message.
If the whole row is encoded as JSON with a known schema or structure, use the JSON
format and
define the structure as the source's columns. For example, a stream of JSON objects similar to the example above could be defined using a statement similar to this:
CREATE STREAM LOGS (LOG STRUCT<CLOUD STRING, APP STRING, INSTANCE INT, ...) WITH (VALUE_FORMAT=JSON, ...)
INITCAP
¶
Since: 0.6.0
1 |
|
Capitalize the first letter in each word and convert all other letters to lowercase. Words are delimited by whitespace.
INSTR
¶
Since: 0.10.0
1 |
|
Returns the position of substring
in string
. The first character is at position 1.
If position
is provided, search starts from the specified position.
Negative position
causes the search to work from end to start of string
.
If occurrence
is provided, the position of n-th occurrence is returned.
If substring
is not found, the return value is 0.
Examples:
1 2 3 4 5 6 |
|
LCASE
¶
Since: -
1 |
|
Convert a string to lowercase.
LEN
¶
Since: -
1 |
|
The length of a string.
LPAD
¶
Since: 0.10.0
1 |
|
Pads the input string, beginning from the left, with the specified padding string, until the target length is reached. If the input string is longer than the specified target length, it is truncated.
If the padding string is empty or NULL, or the target length is negative, NULL is returned.
Examples:
1 2 3 4 |
|
MASK
¶
Since: 0.6.0
1 |
|
Convert a string to a masked or obfuscated version of itself. The optional arguments following the input string to be masked are the characters to be substituted for upper-case, lower-case, numeric, and other characters of the input, respectively.
If the mask characters are omitted then the default values, shown in the following example, are applied.
Set a given mask character to NULL to prevent any masking of that character
type. For example: MASK("My Test $123")
will return Xx-Xxxx--nnn
, applying
all default masks. MASK("My Test $123", '*', NULL, '1', NULL)
will yield
*y *est $111
.
MASK_KEEP_LEFT
¶
Since: 0.6.0
1 |
|
Similar to the MASK
function above, except
that the first or left-most numChars
characters will not be masked in any way.
For example: MASK_KEEP_LEFT("My Test $123", 4)
will return My Txxx--nnn
.
MASK_KEEP_RIGHT
¶
Since: 0.6.0
1 |
|
Similar to the MASK
function above, except
that the last or right-most numChars
characters will not be masked in any way.
For example:MASK_KEEP_RIGHT("My Test $123", 4)
will return Xx-Xxxx-$123
.
MASK_LEFT
¶
Since: 0.6.0
1 |
|
Similar to the MASK
function above, except
that only the first or left-most numChars
characters will have any masking applied to them.
For example, MASK_LEFT("My Test $123", 4)
will return Xx-Xest $123
.
MASK_RIGHT
¶
Since: 0.6.0
1 |
|
Similar to the MASK
function above, except
that only the last or right-most numChars
characters will have any masking applied to them.
For example: MASK_RIGHT("My Test $123", 4)
will return My Test -nnn
.
REPLACE
¶
Since: 0.6.0
1 |
|
Replace all instances of a substring in a string with a new string.
REGEXP_EXTRACT
¶
Since: 0.8.0
1 |
|
1 |
|
Extract the first subtring matched by the regex pattern from the input.
A capturing group number can also be specified in order to return that specific group. If a number isn't specified, the entire substring is returned by default.
For example, REGEXP_EXTRACT("(.*) (.*)", 'hello there', 2)
returns "there".
REGEXP_EXTRACT_ALL
¶
Since: 0.10.0
1 |
|
1 |
|
Extract all subtrings matched by the regex pattern from the input.
A capturing group number can also be specified in order to return that specific group. If a number isn't specified, the entire substring is returned by default.
For example, REGEXP_EXTRACT("(\\w+) (\\w+)", 'hello there nice day', 2)
returns ['there', 'day']
.
REGEXP_REPLACE
¶
Since: 0.10.0
1 |
|
Replace all matches of a regex in an input string with a new string. If either the input string, regular expression, or new string is null, the result is null.
REGEXP_SPLIT_TO_ARRAY
¶
Since: 0.10.0
1 |
|
Splits a string into an array of substrings based
on a regular expression. If there is no match,
the original string is returned as the only
element in the array. If the regular expression is empty,
then all characters in the string are split.
If either the string or the regular expression is NULL
, a
NULL value is returned.
If the regular expression is found at the beginning or end of the string, or there are contiguous matches, then an empty element is added to the array.
RPAD
¶
Since: 0.10.0
1 |
|
Pads the input string, starting from the end, with the specified padding string until the target length is reached. If the input string is longer than the specified target length it will be truncated.
If the padding string is empty or NULL, or the target length is negative, then NULL is returned.
Examples:
1 2 3 |
|
SPLIT
¶
Since: 0.6.0
1 |
|
Splits a string into an array of substrings based on a delimiter. If the delimiter is not found, then the original string is returned as the only element in the array. If the delimiter is empty, then all characters in the string are split. If either, string or delimiter, are NULL, then a NULL value is returned.
If the delimiter is found at the beginning or end of the string, or there are contiguous delimiters, then an empty space is added to the array.
SPLIT_TO_MAP
¶
Since: 0.10.0
1 |
|
Splits a string into key-value pairs and creates a map from them. The
entryDelimiter
splits the string into key-value pairs which are then split by kvDelimiter
. If the same key is present multiple times in the input, the latest value for that key is returned.
Returns NULL if the input text is NULL. Returns NULL if either of the delimiters is NULL or an empty string.
Example:
1 |
|
SUBSTRING
¶
Since: -
1 |
|
1 |
|
Returns a substring of str
that starts at
pos
(first character is at position 1) and
has length len
, or continues to the end of
the string.
For example, SUBSTRING("stream", 1, 4)
returns "stre".
TRIM
¶
Since: -
1 |
|
Trim the spaces from the beginning and end of a string.
UCASE
¶
Since: -
1 |
|
Convert a string to uppercase.
UUID
¶
Since: 0.10.0
1 |
|
Create a Universally Unique Identifier (UUID) generated according to RFC 4122. A call to UUID() returns a value conforming to UUID version 4, sometimes called "random UUID", as described in RFC 4122. The value is a 128-bit number represented as a string of five hexadecimal numbers aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee.
Nulls¶
COALESCE
¶
Since: 0.9.0
1 |
|
Returns the first parameter that is not NULL. All parameters must be of the same type.
Where the parameter type is a complex type, for example ARRAY
or STRUCT
, the contents of the
complex type are not inspected. The behaviour is the same: the first NOT NULL element is returned.
IFNULL
¶
Since: -
1 |
|
If the provided expression
is NULL, returns altValue
, otherwise, returns expression
.
Where the parameter type is a complex type, for example ARRAY
or STRUCT
, the contents of the
complex type are not inspected.
Date and time¶
UNIX_DATE
¶
Since: 0.6.0
1 |
|
Gets an integer representing days since epoch. The returned timestamp may differ depending on the local time of different ksqlDB Server instances.
UNIX_TIMESTAMP
¶
Since: 0.6.0
1 |
|
Gets the Unix timestamp in milliseconds, represented as a BIGINT. The returned timestamp may differ depending on the local time of different ksqlDB Server instances.
DATETOSTRING
¶
Since: -
1 |
|
Converts an integer representation of a date into a string representing the
date in the given format. Single quotes in the timestamp format can be escaped
with two successive single quotes, ''
, for example: 'yyyy-MM-dd''T'''
.
The integer represents days since epoch matching the encoding used by
Connect dates.
STRINGTODATE
¶
Since: -
1 |
|
Converts a string representation of a date in the
given format into an integer representing days
since epoch. Single quotes in the timestamp
format can be escaped with two successive single
quotes, ''
, for example: 'yyyy-MM-dd''T'''
.
STRINGTOTIMESTAMP
¶
Since: -
1 |
|
Converts a string value in the given
format into the BIGINT value
that represents the millisecond timestamp. Single
quotes in the timestamp format can be escaped with
two successive single quotes, ''
, for
example: 'yyyy-MM-dd''T''HH:mm:ssX'
.
TIMEZONE is an optional parameter and it is a
java.util.TimeZone
ID format, for example: "UTC",
"America/Los_Angeles", "PDT", "Europe/London". For
more information on timestamp formats, see
DateTimeFormatter.
TIMESTAMPTOSTRING
¶
Since: -
1 |
|
Converts a BIGINT millisecond timestamp value into
the string representation of the timestamp in
the given format. Single quotes in the
timestamp format can be escaped with two
successive single quotes, ''
, for example:
'yyyy-MM-dd''T''HH:mm:ssX'
.
TIMEZONE is an optional parameter and it is a
java.util.TimeZone ID format, for example: "UTC",
"America/Los_Angeles", "PDT", "Europe/London". For
more information on timestamp formats, see
DateTimeFormatter.
URLs¶
Note
All ksqlDB URL functions assume URI syntax defined in
RFC 39386. For more information on the
structure of a URI, including definitions of the various components, see
Section 3 of the RFC. For encoding/decoding, the
application/x-www-form-urlencoded
convention is followed.
URL_DECODE_PARAM
¶
1 |
|
Since: 0.6.0
Unescapes the URL-param-encoded
_ value in col1
. This is the inverse of
URL_ENCODE_PARAM
.
- Input:
'url%20encoded
- Output:
url encoded
URL_ENCODE_PARAM
¶
1 |
|
Since: 0.6.0
Escapes the value of col1
such that it can
safely be used in URL query parameters. Note that
this is not the same as encoding a value for use
in the path portion of a URL.
- Input:
url encoded
- Output:
'url%20encoded
URL_EXTRACT_FRAGMENT
¶
1 |
|
Since: 0.6.0
Extract the fragment portion of the specified
value. Returns NULL if url
is not a valid URL
or if the fragment does not exist. Any encoded
value will be decoded.
- Input:
http://test.com#frag
, - Output:
frag
- Input:
http://test.com#frag%20space
, - Output:
frag space
URL_EXTRACT_HOST
¶
1 |
|
Since: 0.6.0
Extract the host-name portion of the specified
value. Returns NULL if the url
is not a valid
URI according to RFC-2396.
- Input:
http://test.com:8080/path
, - Output:
test.com
URL_EXTRACT_PARAMETER
¶
Since: 0.6.0
1 |
|
Extract the value of the requested parameter from
the query-string of url
. Returns NULL
if the parameter is not present, has no value
specified for it in the query-string, or url
is not a valid URI. Encodes the param and decodes
the output (see examples).
To get all of the parameter values from a
URL as a single string, see URL_EXTRACT_QUERY.
- Input:
http://test.com?a%20b=c%20d
,a b
- Output:
c d
- Input:
http://test.com?a=foo&b=bar
,b
- Output:
bar
URL_EXTRACT_PATH
¶
1 |
|
Since: 0.6.0
Extracts the path from url
.
Returns NULL if url
is not a valid URI but
returns an empty string if the path is empty.
- Input:
http://test.com/path/to#a
- Output:
path/to
URL_EXTRACT_PORT
¶
1 |
|
Since: 0.6.0
Extract the port number from url
.
Returns NULL if url
is not a valid URI or does
not contain an explicit port number.
- Input:
http://localhost:8080/path
- Output:
8080
URL_EXTRACT_PROTOCOL
¶
1 |
|
Since: 0.6.0
Extract the protocol from url
. Returns NULL if
url
is an invalid URI or has no protocol.
- Input:
http://test.com?a=foo&b=bar
- Output:
http
URL_EXTRACT_QUERY
¶
Since: 0.6.0
1 |
|
Extract the decoded query-string portion of
url
. Returns NULL if no query-string is
present or url
is not a valid URI.
- Input:
http://test.com?a=foo%20bar&b=baz
- Output:
a=foo bar&b=baz