MySQL 实用语句集合

参考链接[用户]：http://blog.csdn.net/dmtnewtons_blog/article/details/9136339

参考链接[属性]：http://stackoverflow.com/questions/15821532/get-current-auto-increment-value-for-any-table

参考链接[索引]：http://blog.csdn.net/dmtnewtons_blog/article/details/18605947

1、查询数据库中表的属性：

SHOW TABLE STATUS FROM `DatabaseName` LIKE 'TableName' ;

结果举例：

+--------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+-------------------------------------------------+---------+
| Name         | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time         | Update_time | Check_time | Collation       | Checksum | Create_options                                  | Comment |
+--------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+-------------------------------------------------+---------+
| TableName    | InnoDB |      10 | Compact    |    2 |           8192 |       16384 |               0 |            0 |  11534336 |              8 | 2014-03-06 02:13:49 | NULL        | NULL       | utf8_general_ci |     NULL | checksum=1 delay_key_write=1 row_format=DYNAMIC |         |
+--------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+-------------------------------------------------+---------+

2、获取数据库表中自增字段的值：

SELECT `AUTO_INCREMENT`
FROM  INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'DatabaseName'
AND   TABLE_NAME   = 'TableName';

结果举例：

+----------------+
| AUTO_INCREMENT |
+----------------+
|              8 |
+----------------+

3、创建MySQL登录用户，可以任意地址远端访问，同root权限：

grant all on *.* to 'remote'@'%' identified by 'password';

结果举例：

#/usr/local/mysql/bin/mysql -h 1.1.1.1 -u remote -p

4、清空表：

TRUNCATE `TableName`;

5、查看表中的索引：

EXPLAIN SELECT `id`,`username` FROM `TableName`;

结果举例：

+----+-------------+-----------+-------+---------------+--------------+---------+------+------+-------------+
| id | select_type | table     | type  | possible_keys | key          | key_len | ref  | rows | Extra       |
+----+-------------+-----------+-------+---------------+--------------+---------+------+------+-------------+
|  1 | SIMPLE      | TableName | index | NULL          | idx_username | 98      | NULL |    1 | Using index |
+----+-------------+-----------+-------+---------------+--------------+---------+------+------+-------------+

6、字符串截取：

[1] 在路径中截取文件名：

SELECT SUBSTRING_INDEX('C:\\dir\\file.txt', '\\', -1);    //windows
SELECT SUBSTRING_INDEX('/usr/local/ade.c', '/', -1);      //Linux

[2] 返回当前 MySQL用户名和机主名

mysql> SELECT USER();

        -> 'davida@localhost'

这个值指示了你指定的连接服务器时的用户名,及你所连接的客户主机。这个值可以和CURRENT_USER()的值不同。

你可以这样提取用户名部分：

mysql> SELECT SUBSTRING_INDEX(USER(),'@',1);

        -> 'davida'

由于 USER() 返回一个utf8 字符集中的值，你也应确保'@'字符串文字在该字符集中得到解释：

mysql> SELECT SUBSTRING_INDEX(USER(),_utf8'@',1);

        -> 'davida'