mysql学习

存储过程和函数：

mysql> delimiter //
mysql> CREATE PROCEDURE count_licence (out count int)
-> BEGIN
->     SELECT count(*) INTO count from test_licence;
-> END
-> //
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;
mysql> CALL count_licence(@a);
Query OK, 0 rows affected (0.02 sec)

mysql> select @a;
+-------+
| @a    |
+-------+
| 89805 |
+-------+
1 row in set (0.00 sec)

mysql> SHOW PROCEDURE status like 'count%';
+-----------+---------------+-----------+---------+---------------------+---------------------+---------------+---------+----------------------+----------------------+--------------------+
| Db        | Name          | Type      | Definer | Modified            | Created             | Security_type | Comment | character_set_client | collation_connection | Database Collation |
+-----------+---------------+-----------+---------+---------------------+---------------------+---------------+---------+----------------------+----------------------+--------------------+
| test_db | count_licence | PROCEDURE | root@%  | 2017-01-06 13:54:05 | 2017-01-06 13:54:05 | DEFINER       |         | utf8                 | utf8_general_ci      | utf8_general_ci    |
+-----------+---------------+-----------+---------+---------------------+---------------------+---------------+---------+----------------------+----------------------+--------------------+
1 row in set (0.00 sec)

可能出现的错误：

ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled
(you *might* want to use the less safe log_bin_trust_function_creators variable)

这是我们开启了bin-log, 我们就必须指定我们的函数是否是
1 DETERMINISTIC 不确定的
2 NO SQL 没有SQl语句，当然也不会修改数据
3 READS SQL DATA 只是读取数据，当然也不会修改数据
4 MODIFIES SQL DATA 要修改数据
5 CONTAINS SQL 包含了SQL语句