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MySQL之系系统信息函数

1.VERSION()

用法:返回MySQL服务器的版本

举例:

mysql> select VERSION();+-----------+| VERSION() |+-----------+| 5.6.10    |+-----------+1 row in set (0.00 sec)

2.USER(),SYSTEM_USER()

用法:返回当前登录用户名

举例:

mysql> select  USER();+----------------+| USER()         |+----------------+| root@localhost |+----------------+1 row in set (0.00 sec)mysql> select  SYSTEM_USER();+----------------+| SYSTEM_USER()  |+----------------+| root@localhost |+----------------+1 row in set (0.00 sec)

3.DATABASE()

用法:返回当前数据库名

举例:

mysql> select DATABASE();+------------+| DATABASE() |+------------+| test       |+------------+1 row in set (0.00 sec)

4.FOUND_ROWS()

用法:将最后一个SELECT查询(没有以LIMIT语句进行限制)返回的记录行数返回

举例:

mysql> select FOUND_ROWS();+--------------+| FOUND_ROWS() |+--------------+|            1 |+--------------+1 row in set (0.00 sec)

5.LAST_INSERT_ID()

用法:返回由系统自动产生的最后一个AUTOINCREMENT ID的值(多条记录同时插入时返回的是第一条的记录的插入的ID)

举例:

mysql> select LAST_INSERT_ID();+------------------+| LAST_INSERT_ID() |+------------------+|                0 |+------------------+1 row in set (0.02 sec)

6.CONNECTION_ID()

用法:返回当前客户的连接ID

举例:

mysql> select CONNECTION_ID();+-----------------+| CONNECTION_ID() |+-----------------+|               1 |+-----------------+1 row in set (0.00 sec)

7.CHARSET(str)

用法;返回字符串str的字符集

举例:

mysql> select  CHARSET(MYSQL);+------------------+| CHARSET(MYSQL) |+------------------+| utf8             |+------------------+1 row in set (0.04 sec)

MySQL之系系统信息函数