GoogleSQL for Spanner supports the following hash functions.
Function list
| Name | Summary |
|---|---|
FARM_FINGERPRINT
|
Computes the fingerprint of a STRING
or BYTES
value, using the FarmHash Fingerprint64 algorithm. |
SHA1
|
Computes the hash of a STRING
or BYTES
value, using the SHA-1 algorithm. |
SHA256
|
Computes the hash of a STRING
or BYTES
value, using the SHA-256 algorithm. |
SHA512
|
Computes the hash of a STRING
or BYTES
value, using the SHA-512 algorithm. |
FARM_FINGERPRINT
FARM_FINGERPRINT
(
value
)
Description
Computes the fingerprint of the STRING
or BYTES
input using the Fingerprint64
function from the open-source FarmHash library
. The output
of this function for a particular input will never change.
Return type
INT64
Examples
WITH
example
AS
(
SELECT
1
AS
x
,
"foo"
AS
y
,
true
AS
z
UNION
ALL
SELECT
2
AS
x
,
"apple"
AS
y
,
false
AS
z
UNION
ALL
SELECT
3
AS
x
,
""
AS
y
,
true
AS
z
)
SELECT
*
,
FARM_FINGERPRINT
(
CONCAT
(
CAST
(
x
AS
STRING
),
y
,
CAST
(
z
AS
STRING
)))
AS
row_fingerprint
FROM
example
;
/*---+-------+-------+----------------------*
| x | y | z | row_fingerprint |
+---+-------+-------+----------------------+
| 1 | foo | true | -1541654101129638711 |
| 2 | apple | false | 2794438866806483259 |
| 3 | | true | -4880158226897771312 |
*---+-------+-------+----------------------*/
SHA1
SHA1
(
input
)
Description
Computes the hash of the input using the SHA-1 algorithm
. The input can either be STRING
or BYTES
. The string version treats the input as an array of bytes.
This function returns 20 bytes.
Return type
BYTES
Example
SELECT
SHA1
(
"Hello World"
)
as
sha1
;
-- Note that the result of SHA1 is of type BYTES, displayed as a base64-encoded string.
/*------------------------------*
| sha1 |
+------------------------------+
| Ck1VqNd45QIvq3AZd8XYQLvEhtA= |
*------------------------------*/
SHA256
SHA256
(
input
)
Description
Computes the hash of the input using the SHA-256 algorithm
. The input can either be STRING
or BYTES
. The string version treats the input as an array of bytes.
This function returns 32 bytes.
Return type
BYTES
Example
SELECT
SHA256
(
"Hello World"
)
as
sha256
;
SHA512
SHA512
(
input
)
Description
Computes the hash of the input using the SHA-512 algorithm
. The input can either be STRING
or BYTES
. The string version treats the input as an array of bytes.
This function returns 64 bytes.
Return type
BYTES
Example
SELECT
SHA512
(
"Hello World"
)
as
sha512
;
