function returns the normalized statement digest. For information about statement digesting, see Section 27.10, “Performance Schema Statement Digests and Sampling” . 

Both functions use the MySQL parser to parse the statement. If parsing fails, an error occurs. The error message includes the parse error only if the statement is provided as a literal string. 

The max_digest_length  system variable determines the maximum number of bytes available to these functions for computing normalized statement digests. 

mysql> SET @stmt = ’SELECT * FROM mytable WHERE cola = 10 AND colb = 20’; mysql> SELECT STATEMENT_DIGEST(@stmt); +------------------------------------------------------------------+ | STATEMENT_DIGEST(@stmt) | +------------------------------------------------------------------+ | 3bb95eeade896657c4526e74ff2a2862039d0a0fe8a9e7155b5fe492cbd78387 | +------------------------------------------------------------------+ mysql> SELECT STATEMENT_DIGEST_TEXT(@stmt); +----------------------------------------------------------+ | STATEMENT_DIGEST_TEXT(@stmt) | +----------------------------------------------------------+ | SELECT * FROM ‘mytable‘ WHERE ‘cola‘ = ? AND ‘colb‘ = ? | +----------------------------------------------------------+ 

• STATEMENT_DIGEST_TEXT( statement ) 

Given an SQL statement as a string, returns the normalized statement digest as a string in the connection character set, or NULL  if the argument is NULL . For additional discussion and examples, see the description of the related STATEMENT_DIGEST()  function. 

• UNCOMPRESS( string_to_uncompress ) 

Uncompresses a string compressed by the COMPRESS()  function. If the argument is not a compressed value, the result is NULL . This function requires MySQL to have been compiled with a compression library such as zlib . Otherwise, the return value is always NULL . 

mysql> SELECT UNCOMPRESS(COMPRESS(’any string’)); -> ’any string’ mysql> SELECT UNCOMPRESS(’any string’); -> NULL 

• UNCOMPRESSED_LENGTH( compressed_string ) 

Returns the length that the compressed string had before being compressed. 

mysql> SELECT UNCOMPRESSED_LENGTH(COMPRESS(REPEAT(’a’,30))); -> 30 

• VALIDATE_PASSWORD_STRENGTH( str ) 

Given an argument representing a plaintext password, this function returns an integer to indicate how strong the password is. The return value ranges from 0 (weak) to 100 (strong). 

Password assessment by VALIDATE_PASSWORD_STRENGTH()  is done by the validate_password component. If that component is not installed, the function always returns 0. For information about installing validate_password , see Section 6.4.3, “The Password Validation Component” . To examine or configure the parameters that affect password testing, check or set the system variables implemented by validate_password . See Section 6.4.3.2, “Password Validation Options and Variables” . 

The password is subjected to increasingly strict tests and the return value reflects which tests were satisfied, as shown in the following table. In addition, if the 

