All other values of x
are invalid and throw an error instead of casting to a boolean.
A string is case-insensitive when converting to a boolean.
CAST(expressionASBYTES[format_clause])
Description
GoogleSQL supports casting to BYTES
. The expression
parameter can represent an expression for these data types:
BYTES
STRING
Format clause
When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression
is a STRING
.
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | BYTES | Strings are cast to bytes using UTF-8 encoding. For example, the string "©", when cast to bytes, would become a 2-byte sequence with the hex values C2 and A9. |
CAST(expressionASDATE[format_clause])
Description
GoogleSQL supports casting to DATE
. The expression
parameter can represent an expression for these data types:
STRING
DATETIME
TIMESTAMP
Format clause
When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression
is a STRING
.
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | DATE | When casting from string to date, the string must conform to the supported date literal format, and is independent of time zone. If the string expression is invalid or represents a date that's outside of the supported min/max range, then an error is produced. |
TIMESTAMP | DATE | Casting from a timestamp to date effectively truncates the timestamp as of the default time zone. |
CAST(expressionASDATETIME[format_clause])
Description
GoogleSQL supports casting to DATETIME
. The expression
parameter can represent an expression for these data types:
STRING
DATETIME
TIMESTAMP
Format clause
When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression
is a STRING
.
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | DATETIME | When casting from string to datetime, the string must conform to the supported datetime literal format, and is independent of time zone. If the string expression is invalid or represents a datetime that's outside of the supported min/max range, then an error is produced. |
TIMESTAMP | DATETIME | Casting from a timestamp to datetime effectively truncates the timestamp as of the default time zone. |
CAST(expressionASFLOAT64)
Description
GoogleSQL supports casting to floating point types. The expression
parameter can represent an expression for these data types:
INT64
FLOAT64
NUMERIC
BIGNUMERIC
STRING
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
INT64 | FLOAT64 | Returns a close but potentially not exact floating point value. |
NUMERIC | FLOAT64 | NUMERIC will convert to the closest floating point number with a possible loss of precision. |
BIGNUMERIC | FLOAT64 | BIGNUMERIC will convert to the closest floating point number with a possible loss of precision. |
STRING | FLOAT64 | Returns x as a floating point value, interpreting it as having the same form as a valid floating point literal. Also supports casts from "[+,-]inf" to [,-]Infinity , "[+,-]infinity" to [,-]Infinity , and "[+,-]nan" to NaN . Conversions are case-insensitive. |
CAST(expressionASINT64)
Description
GoogleSQL supports casting to integer types. The expression
parameter can represent an expression for these data types:
INT64
FLOAT64
NUMERIC
BIGNUMERIC
BOOL
STRING
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
FLOAT64 | INT64 | Returns the closest integer value. Halfway cases such as 1.5 or -0.5 round away from zero. |
BOOL | INT64 | Returns 1 if x is TRUE , 0 otherwise. |
STRING | INT64 | A hex string can be cast to an integer. For example, 0x123 to 291 or -0x123 to -291 . |
Examples
If you are working with hex strings (0x123
), you can cast those strings as integers:
SELECT'0x123'ashex_value,CAST('0x123'asINT64)ashex_to_int;/*-----------+------------* | hex_value | hex_to_int | +-----------+------------+ | 0x123 | 291 | *-----------+------------*/
SELECT'-0x123'ashex_value,CAST('-0x123'asINT64)ashex_to_int;/*-----------+------------* | hex_value | hex_to_int | +-----------+------------+ | -0x123 | -291 | *-----------+------------*/
CAST(expressionASINTERVAL)
Description
GoogleSQL supports casting to INTERVAL
. The expression
parameter can represent an expression for these data types:
STRING
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | INTERVAL | When casting from string to interval, the string must conform to either ISO 8601 Duration standard or to interval literal format 'Y-M D H:M:S.F'. Partial interval literal formats are also accepted when they aren't ambiguous, for example 'H:M:S'. If the string expression is invalid or represents an interval that is outside of the supported min/max range, then an error is produced. |
Examples
SELECTinput,CAST(inputASINTERVAL)ASoutputFROMUNNEST(['1-2 3 10:20:30.456','1-2','10:20:30','P1Y2M3D','PT10H20M30,456S'])input/*--------------------+--------------------* | input | output | +--------------------+--------------------+ | 1-2 3 10:20:30.456 | 1-2 3 10:20:30.456 | | 1-2 | 1-2 0 0:0:0 | | 10:20:30 | 0-0 0 10:20:30 | | P1Y2M3D | 1-2 3 0:0:0 | | PT10H20M30,456S | 0-0 0 10:20:30.456 | *--------------------+--------------------*/
CAST(expressionASNUMERIC)
Description
GoogleSQL supports casting to NUMERIC
. The expression
parameter can represent an expression for these data types:
INT64
FLOAT64
NUMERIC
BIGNUMERIC
STRING
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
FLOAT64 | NUMERIC | The floating point number will round half away from zero. Casting a NaN , +inf or -inf will return an error. Casting a value outside the range of NUMERIC returns an overflow error. |
STRING | NUMERIC | The numeric literal contained in the string must not exceed the maximum precision or range of the NUMERIC type, or an error will occur. If the number of digits after the decimal point exceeds nine, then the resulting NUMERIC value will round half away from zero. to have nine digits after the decimal point. |
CAST(expressionASRANGE)
Description
GoogleSQL supports casting to RANGE
. The expression
parameter can represent an expression for these data types:
STRING
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | RANGE | When casting from string to range, the string must conform to the supported range literal format. If the string expression is invalid or represents a range that's outside of the supported subtype min/max range, then an error is produced. |
Examples
SELECTCAST('[2020-01-01, 2020-01-02)'ASRANGE<DATE>)ASstring_to_range/*----------------------------------------* | string_to_range | +----------------------------------------+ | [DATE '2020-01-01', DATE '2020-01-02') | *----------------------------------------*/
SELECTCAST('[2014-09-27 12:30:00.45, 2016-10-17 11:15:00.33)'ASRANGE<DATETIME>)ASstring_to_range/*------------------------------------------------------------------------* | string_to_range | +------------------------------------------------------------------------+ | [DATETIME '2014-09-27 12:30:00.45', DATETIME '2016-10-17 11:15:00.33') | *------------------------------------------------------------------------*/
SELECTCAST('[2014-09-27 12:30:00+08, 2016-10-17 11:15:00+08)'ASRANGE<TIMESTAMP>)ASstring_to_range-- Results depend upon where this query was executed./*---------------------------------------------------------------------------* | string_to_range | +---------------------------------------------------------------------------+ | [TIMESTAMP '2014-09-27 12:30:00+08', TIMESTAMP '2016-10-17 11:15:00 UTC') | *---------------------------------------------------------------------------*/
SELECTCAST('[UNBOUNDED, 2020-01-02)'ASRANGE<DATE>)ASstring_to_range/*--------------------------------* | string_to_range | +--------------------------------+ | [UNBOUNDED, DATE '2020-01-02') | *--------------------------------*/
SELECTCAST('[2020-01-01, NULL)'ASRANGE<DATE>)ASstring_to_range/*--------------------------------* | string_to_range | +--------------------------------+ | [DATE '2020-01-01', UNBOUNDED) | *--------------------------------*/
CAST(expressionASSTRING[format_clause[ATTIMEZONEtimezone_expr]])
Description
GoogleSQL supports casting to STRING
. The expression
parameter can represent an expression for these data types:
INT64
FLOAT64
NUMERIC
BIGNUMERIC
BOOL
BYTES
TIME
DATE
DATETIME
TIMESTAMP
RANGE
INTERVAL
STRING
Format clause
When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression
is one of these data types:
INT64
FLOAT64
NUMERIC
BIGNUMERIC
BYTES
TIME
DATE
DATETIME
TIMESTAMP
The format clause for STRING
has an additional optional clause called AT TIME ZONE timezone_expr
, which you can use to specify a specific time zone to use during formatting of a TIMESTAMP
. If this optional clause isn't included when formatting a TIMESTAMP
, your current time zone is used.
For more information, see the following topics:
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
FLOAT64 | STRING | Returns an approximate string representation. A returned NaN or 0 will not be signed. |
BOOL | STRING | Returns "true" if x is TRUE , "false" otherwise. |
BYTES | STRING | Returns x interpreted as a UTF-8 string.For example, the bytes literal b'\xc2\xa9' , when cast to a string, is interpreted as UTF-8 and becomes the unicode character "©".An error occurs if x isn't valid UTF-8. |
TIME | STRING | Casting from a time type to a string is independent of time zone and is of the form HH:MM:SS . |
DATE | STRING | Casting from a date type to a string is independent of time zone and is of the form YYYY-MM-DD . |
DATETIME | STRING | Casting from a datetime type to a string is independent of time zone and is of the form YYYY-MM-DD HH:MM:SS . |
TIMESTAMP | STRING | When casting from timestamp types to string, the timestamp is interpreted using the default time zone, UTC. The number of subsecond digits produced depends on the number of trailing zeroes in the subsecond part: the CAST function will truncate zero, three, or six digits. |
INTERVAL | STRING | Casting from an interval to a string is of the form Y-M D H:M:S . |
Examples
SELECTCAST(CURRENT_DATE()ASSTRING)AScurrent_date/*---------------* | current_date | +---------------+ | 2021-03-09 | *---------------*/
SELECTCAST(CURRENT_DATE()ASSTRINGFORMAT'DAY')AScurrent_day/*-------------* | current_day | +-------------+ | MONDAY | *-------------*/
SELECTCAST(TIMESTAMP'2008-12-25 00:00:00+00:00'ASSTRINGFORMAT'YYYY-MM-DD HH24:MI:SS TZH:TZM')ASdate_time_to_string-- Results depend upon where this query was executed./*------------------------------* | date_time_to_string | +------------------------------+ | 2008-12-24 16:00:00 -08:00 | *------------------------------*/
SELECTCAST(TIMESTAMP'2008-12-25 00:00:00+00:00'ASSTRINGFORMAT'YYYY-MM-DD HH24:MI:SS TZH:TZM'ATTIMEZONE'Asia/Kolkata')ASdate_time_to_string-- Because the time zone is specified, the result is always the same./*------------------------------* | date_time_to_string | +------------------------------+ | 2008-12-25 05:30:00 +05:30 | *------------------------------*/
SELECTCAST(INTERVAL3DAYASSTRING)ASinterval_to_string/*--------------------* | interval_to_string | +--------------------+ | 0-0 3 0:0:0 | *--------------------*/
SELECTCAST(INTERVAL"1-2 3 4:5:6.789"YEARTOSECONDASSTRING)ASinterval_to_string/*--------------------* | interval_to_string | +--------------------+ | 1-2 3 4:5:6.789 | *--------------------*/
CAST(expressionASSTRUCT)
Description
GoogleSQL supports casting to STRUCT
. The expression
parameter can represent an expression for these data types:
STRUCT
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRUCT | STRUCT | Allowed if the following conditions are met:
|
CAST(expressionASTIME[format_clause])
Description
GoogleSQL supports casting to TIME. The expression
parameter can represent an expression for these data types:
STRING
TIME
DATETIME
TIMESTAMP
Format clause
When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression
is a STRING
.
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | TIME | When casting from string to time, the string must conform to the supported time literal format, and is independent of time zone. If the string expression is invalid or represents a time that's outside of the supported min/max range, then an error is produced. |
CAST(expressionASTIMESTAMP[format_clause[ATTIMEZONEtimezone_expr]])
Description
GoogleSQL supports casting to TIMESTAMP
. The expression
parameter can represent an expression for these data types:
STRING
DATETIME
TIMESTAMP
Format clause
When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression
is a STRING
.
The format clause for TIMESTAMP
has an additional optional clause called AT TIME ZONE timezone_expr
, which you can use to specify a specific time zone to use during formatting. If this optional clause isn't included, your current time zone is used.
Conversion rules
From | To | Rule(s) when casting x |
---|---|---|
STRING | TIMESTAMP | When casting from string to a timestamp, string_expression must conform to the supported timestamp literal formats, or else a runtime error occurs. The string_expression may itself contain a time zone. If there is a time zone in the string_expression , that time zone is used for conversion, otherwise the default time zone, UTC, is used. If the string has fewer than six digits, then it's implicitly widened. An error is produced if the string_expression is invalid, has more than six subsecond digits (i.e., precision greater than microseconds), or represents a time outside of the supported timestamp range. |
DATE | TIMESTAMP | Casting from a date to a timestamp interprets date_expression as of midnight (start of the day) in the default time zone, UTC. |
DATETIME | TIMESTAMP | Casting from a datetime to a timestamp interprets datetime_expression in the default time zone, UTC. Most valid datetime values have exactly one corresponding timestamp in each time zone. However, there are certain combinations of valid datetime values and time zones that have zero or two corresponding timestamp values. This happens in a time zone when clocks are set forward or set back, such as for Daylight Savings Time. When there are two valid timestamps, the earlier one is used. When there is no valid timestamp, the length of the gap in time (typically one hour) is added to the datetime. |
Examples
The following example casts a string-formatted timestamp as a timestamp:
SELECTCAST("2020-06-02 17:00:53.110+00:00"ASTIMESTAMP)ASas_timestamp-- Results depend upon where this query was executed./*-----------------------------* | as_timestamp | +-----------------------------+ | 2020-06-03 00:00:53.110 UTC | *-----------------------------*/
The following examples cast a string-formatted date and time as a timestamp. These examples return the same output as the previous example.
SELECTCAST('06/02/2020 17:00:53.110'ASTIMESTAMPFORMAT'MM/DD/YYYY HH24:MI:SS.FF3'ATTIMEZONE'UTC')ASas_timestamp
SELECTCAST('06/02/2020 17:00:53.110'ASTIMESTAMPFORMAT'MM/DD/YYYY HH24:MI:SS.FF3'ATTIMEZONE'+00')ASas_timestamp
SELECTCAST('06/02/2020 17:00:53.110 +00'ASTIMESTAMPFORMAT'MM/DD/YYYY HH24:MI:SS.FF3 TZH')ASas_timestamp
PARSE_BIGNUMERIC
PARSE_BIGNUMERIC(string_expression)
Description
Converts a STRING
to a BIGNUMERIC
value.
The numeric literal contained in the string must not exceed the maximum precision or range of the BIGNUMERIC
type, or an error occurs. If the number of digits after the decimal point exceeds 38, then the resulting BIGNUMERIC
value rounds half away from zero to have 38 digits after the decimal point.
-- This example shows how a string with a decimal point is parsed.SELECTPARSE_BIGNUMERIC("123.45")ASparsed;/*--------* | parsed | +--------+ | 123.45 | *--------*/-- This example shows how a string with an exponent is parsed.SELECTPARSE_BIGNUMERIC("123.456E37")ASparsed;/*-----------------------------------------* | parsed | +-----------------------------------------+ | 123400000000000000000000000000000000000 | *-----------------------------------------*/-- This example shows the rounding when digits after the decimal point exceeds 38.SELECTPARSE_BIGNUMERIC("1.123456789012345678901234567890123456789")asparsed;/*------------------------------------------* | parsed | +------------------------------------------+ | 1.12345678901234567890123456789012345679 | *------------------------------------------*/
This function is similar to using the CAST AS BIGNUMERIC
function except that the PARSE_BIGNUMERIC
function only accepts string inputs and allows the following in the string:
Rules for valid input strings:
Rule | Example Input | Output |
---|---|---|
The string can only contain digits, commas, decimal points and signs. | "- 12,34567,89.0" | -123456789 |
Whitespaces are allowed anywhere except between digits. | " - 12.345 " | -12.345 |
Only digits and commas are allowed before the decimal point. | " 12,345,678" | 12345678 |
Only digits are allowed after the decimal point. | "1.234 " | 1.234 |
Use E or e for exponents. After the e , digits and a leading sign indicator are allowed. | " 123.45e-1" | 12.345 |
If the integer part isn't empty, then it must contain at least one digit. | " 0,.12 -" | -0.12 |
If the string contains a decimal point, then it must contain at least one digit. | " .1" | 0.1 |
The string can't contain more than one sign. | " 0.5 +" | 0.5 |
Return Data Type
BIGNUMERIC
Examples
This example shows an input with spaces before, after, and between the sign and the number:
SELECTPARSE_BIGNUMERIC(" - 12.34 ")asparsed;/*--------* | parsed | +--------+ | -12.34 | *--------*/
This example shows an input with an exponent as well as the sign after the number:
SELECTPARSE_BIGNUMERIC("12.34e-1-")asparsed;/*--------* | parsed | +--------+ | -1.234 | *--------*/
This example shows an input with multiple commas in the integer part of the number:
SELECTPARSE_BIGNUMERIC(" 1,2,,3,.45 + ")asparsed;/*--------* | parsed | +--------+ | 123.45 | *--------*/
This example shows an input with a decimal point and no digits in the whole number part:
SELECTPARSE_BIGNUMERIC(".1234 ")asparsed;/*--------* | parsed | +--------+ | 0.1234 | *--------*/
Examples of invalid inputs
This example is invalid because the whole number part contains no digits:
SELECTPARSE_BIGNUMERIC(",,,.1234 ")asparsed;
This example is invalid because there are whitespaces between digits:
SELECTPARSE_BIGNUMERIC("1 23.4 5 ")asparsed;
This example is invalid because the number is empty except for an exponent:
SELECTPARSE_BIGNUMERIC(" e1 ")asparsed;
This example is invalid because the string contains multiple signs:
SELECTPARSE_BIGNUMERIC(" - 12.3 - ")asparsed;
This example is invalid because the value of the number falls outside the range of BIGNUMERIC
:
SELECTPARSE_BIGNUMERIC("12.34E100 ")asparsed;
This example is invalid because the string contains invalid characters:
SELECTPARSE_BIGNUMERIC("$12.34")asparsed;
PARSE_NUMERIC
PARSE_NUMERIC(string_expression)
Description
Converts a STRING
to a NUMERIC
value.
The numeric literal contained in the string must not exceed the maximum precision or range of the NUMERIC
type, or an error occurs. If the number of digits after the decimal point exceeds nine, then the resulting NUMERIC
value rounds half away from zero to have nine digits after the decimal point.
-- This example shows how a string with a decimal point is parsed.SELECTPARSE_NUMERIC("123.45")ASparsed;/*--------* | parsed | +--------+ | 123.45 | *--------*/-- This example shows how a string with an exponent is parsed.SELECTPARSE_NUMERIC("12.34E27")asparsed;/*-------------------------------* | parsed | +-------------------------------+ | 12340000000000000000000000000 | *-------------------------------*/-- This example shows the rounding when digits after the decimal point exceeds 9.SELECTPARSE_NUMERIC("1.0123456789")asparsed;/*-------------* | parsed | +-------------+ | 1.012345679 | *-------------*/
This function is similar to using the CAST AS NUMERIC
function except that the PARSE_NUMERIC
function only accepts string inputs and allows the following in the string:
Rules for valid input strings:
Rule | Example Input | Output |
---|---|---|
The string can only contain digits, commas, decimal points and signs. | "- 12,34567,89.0" | -123456789 |
Whitespaces are allowed anywhere except between digits. | " - 12.345 " | -12.345 |
Only digits and commas are allowed before the decimal point. | " 12,345,678" | 12345678 |
Only digits are allowed after the decimal point. | "1.234 " | 1.234 |
Use E or e for exponents. After the e , digits and a leading sign indicator are allowed. | " 123.45e-1" | 12.345 |
If the integer part isn't empty, then it must contain at least one digit. | " 0,.12 -" | -0.12 |
If the string contains a decimal point, then it must contain at least one digit. | " .1" | 0.1 |
The string can't contain more than one sign. | " 0.5 +" | 0.5 |
Return Data Type
NUMERIC
Examples
This example shows an input with spaces before, after, and between the sign and the number:
SELECTPARSE_NUMERIC(" - 12.34 ")asparsed;/*--------* | parsed | +--------+ | -12.34 | *--------*/
This example shows an input with an exponent as well as the sign after the number:
SELECTPARSE_NUMERIC("12.34e-1-")asparsed;/*--------* | parsed | +--------+ | -1.234 | *--------*/
This example shows an input with multiple commas in the integer part of the number:
SELECTPARSE_NUMERIC(" 1,2,,3,.45 + ")asparsed;/*--------* | parsed | +--------+ | 123.45 | *--------*/
This example shows an input with a decimal point and no digits in the whole number part:
SELECTPARSE_NUMERIC(".1234 ")asparsed;/*--------* | parsed | +--------+ | 0.1234 | *--------*/
Examples of invalid inputs
This example is invalid because the whole number part contains no digits:
SELECTPARSE_NUMERIC(",,,.1234 ")asparsed;
This example is invalid because there are whitespaces between digits:
SELECTPARSE_NUMERIC("1 23.4 5 ")asparsed;
This example is invalid because the number is empty except for an exponent:
SELECTPARSE_NUMERIC(" e1 ")asparsed;
This example is invalid because the string contains multiple signs:
SELECTPARSE_NUMERIC(" - 12.3 - ")asparsed;
This example is invalid because the value of the number falls outside the range of BIGNUMERIC
:
SELECTPARSE_NUMERIC("12.34E100 ")asparsed;
This example is invalid because the string contains invalid characters:
SELECTPARSE_NUMERIC("$12.34")asparsed;
SAFE_CAST
SAFE_CAST(expressionAStypename[format_clause])
Description
When using CAST
, a query can fail if GoogleSQL is unable to perform the cast. For example, the following query generates an error:
SELECTCAST("apple"ASINT64)ASnot_a_number;
If you want to protect your queries from these types of errors, you can use SAFE_CAST
. SAFE_CAST
replaces runtime errors with NULL
s. However, during static analysis, impossible casts between two non-castable types still produce an error because the query is invalid.
SELECTSAFE_CAST("apple"ASINT64)ASnot_a_number;/*--------------* | not_a_number | +--------------+ | NULL | *--------------*/
Some casts can include a format clause, which provides instructions for how to conduct the cast. For example, you could instruct a cast to convert a sequence of bytes to a BASE64-encoded string instead of a UTF-8-encoded string.
The structure of the format clause is unique to each type of cast and more information is available in the section for that cast.
If you are casting from bytes to strings, you can also use the function, SAFE_CONVERT_BYTES_TO_STRING
. Any invalid UTF-8 characters are replaced with the unicode replacement character, U+FFFD
.
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Last updated 2025-04-17 UTC.