有时会在数据表中保存一个serizlie()过的一个php的array变量字符串，当需要使用SQL语言取出某个key的值时可以用到。比如: a:3:{s:1:a;s:12:asdfasdfasdf;s:1:b;i:123123123;s:1:c;s:8:ASDFASDF;} 需要从中取出key是b的内容。 MySQL delimiter $$create functi

有时会在数据表中保存一个serizlie()过的一个php的array变量字符串，当需要使用SQL语言取出某个key的值时可以用到。比如:

a:3:{s:1:"a";s:12:"asdfasdfasdf";s:1:"b";i:123123123;s:1:"c";s:8:"ASDFASDF";}

需要从中取出key是b的内容。

MySQL

delimiter $$

create function get_from_serialized_json

( in_string varchar(255),

in_key varchar(255) )

returns varchar(255)

BEGIN

return trim( '"' from

substring_index(

substring_index(

substring(trim("}" FROM in_string ), locate(concat("\"",in_key,"\""), in_string )+1

) , ";",2

), ":",-1 )) ;

END$$

mysql> show create function get_from_serialized_json\G

*************************** 1. row ***************************

Function: get_from_serialized_json

sql_mode:

Create Function: CREATE DEFINER=`root`@`localhost` FUNCTION `get_from_serialized_json`( in_string varchar(255),

in_key varchar(255) ) RETURNS varchar(255) CHARSET latin1

BEGIN

return trim( '"' from

substring_index(

substring_index(

substring(trim("}" FROM in_string ), locate(concat("\"",in_key,"\""), in_string )+1

) , ";",2

), ":",-1 )) ;

END

character_set_client: latin1

collation_connection: latin1_swedish_ci

Database Collation: latin1_swedish_ci

1 row in set (0.00 sec)

'asdfasdfasdf', 'b'=> 123123123, 'c'=> 'ASDFASDF');

echo serialize($a);

mysql> set @a ='a:3:{s:1:"a";s:12:"asdfasdfasdf";s:1:"b";i:123123123;s:1:"c";s:8:"ASDFASDF";}';

Query OK, 0 rows affected (0.00 sec)

mysql>

mysql> select get_from_serialized_json(@a,"a");

+----------------------------------+

| get_from_serialized_json(@a,"a") |

+----------------------------------+

| asdfasdfasdf |

+----------------------------------+

1 row in set (0.00 sec)

mysql> select get_from_serialized_json(@a,"b");

+----------------------------------+

| get_from_serialized_json(@a,"b") |

+----------------------------------+

| 123123123 |

+----------------------------------+

1 row in set (0.00 sec)

mysql> select get_from_serialized_json(@a,"c");

+----------------------------------+

| get_from_serialized_json(@a,"c") |

+----------------------------------+

| ASDFASDF |

+----------------------------------+

1 row in set (0.00 sec)

mysql>

mysql> drop function get_from_serialized_json ;

Query OK, 0 rows affected (0.00 sec)

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