Returns a hash value that is calculated by using a string expression that is specified by expr. If the values calculated by a string expression are the same, a consistent hash value is returned.
Syntax
mask_hash(<expr>)Parameters
expr: required. A string expression that is used to calculate a hash value. The STRING, CHAR, VARCHAR, and BINARY types are supported.
Return value
A hash value that is calculated by using a string expression is returned. The fixed length of the hash value is 64 characters. If a non-string expression is used, the value null is returned. This rule also applies to the Hive-compatible mode.
Examples
For non-string expressions, NULL is returned. The hash algorithm is SHA256. A hexadecimal string of 64 characters in length is returned.
-- Return a hash value for the string abc.
select mask_hash("abc");
-- The following result is returned:
+------------+
| _c0 |
+------------+
| ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad |
+------------+
-- The return value is null if a non-string expression is used.
select mask_hash(100);
-- The following result is returned:
+------------+
| _c0 |
+------------+
| NULL |
+------------+Related functions
MASK_HASH is a string function. For more information about functions related to string searches and conversion, see String functions.