mysql数据库常用的查询语句(单表查询)

1 使用select语句查询一个数据表 select* from 数据表名; 2 查询表中的一个字段或多个字段 select 字段1,字段2 from 数据表; 3 查询表中指定的数据信息 select* from数据表名order by id desc limit 2,1; //查询的数据按id倒序排序 4 查询指定路径 Select* f

  1   使用select语句查询一个数据表

              select* from 数据表名;

  2  查询表中的一个字段或多个字段

              select 字段1,字段2 from 数据表;

  3  查询表中指定的数据信息

              select* from数据表名order by id desc limit 2,1;  //查询的数据按id倒序排序

  4  查询指定路径

              Select* from 数据表 where 属性 = ‘…’;

  5  带IN 关键字的查询

              Select* from 数据表 where 字段 [NOT] IN (字段值1，字段值2…字段值n);

例如：

              mysql>select * from library where price in (99,50);

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

| id | name         | author |price |

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

|  1 | java范例大全 | 张帆  | 99    |

|  2 | mySQL        | 潘凯华 | 50    |

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

              mysql>select * from library where price NOT IN(99,50);

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

| id | name          | author| price |

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

|  3 | SQLserver2005 | 刘智勇 | 80    |

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

6 带BETWEEN and 的范围查询

select * from 数据表 where 字段 [NOT] BETWEEN 取值1 and 取值2；

例如：

       mysql> select * from country where idBETWEEN 2 and 4;

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

| id | name     | population | area | language |

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

|  2 | American | 489        | 60  | English  |

|  3 | Japan    | 89        | 30   | Jpanese  |

|  4 | England  | 2         | 300  | English  |

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

3 rows in set(0.09 sec)

mysql> select* from country where id NOT BETWEEN 2 and 4;

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

| id | name  | population | area | language |

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

|  1 | china | 13         | 960 | chinese  |

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

7  带like的字符匹配查询

(1)   select * from 数据表 where 属性 like '%SQL%'；//查询属性中包含SQL字符的数据

(2)   select * from 数据表 where 属性 like 'a%b';// //查询属性中以a开头以b结尾的字符串的数据

(3)   select * from 数据表 where 属性 like 'm_n';//查询属性中以m开头以n结尾的3个字符的数据，中间的‘_’只能代表一个字符

例如：

mysql> select * from library where name like '%SQL%';

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

| id | name          | author| price |

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

|  2 | mySQL         | 潘凯华 | 50    |

|  3 | SQLserver2005 | 刘智勇 | 80    |

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

mysql> select * from library where name like 'myS_L';

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

| id | name  | author | price|

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

|  2 | mySQL | 潘凯华 | 50    |

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

8  带AND的多条件查询

    mysql> select * from library whereprice=50 and name like 'myS_L';

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

| id | name  | author | price |

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

| 2 | mySQL | 潘凯华 | 50    |

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

9  带OR的多条件查询

      mysql> select * from library where price=50or price=99;

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

| id | name         | author | price |

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

| 1 | java范例大全 | 张帆  | 99    |

| 2 | mySQL        | 潘凯华 | 50    |

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

10 用DISTINCT关键字去除结果中的重复行

       例如：

         原表：mysql> select * from library;

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

| id | name          | author | price |

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

| 1 | java范例大全  | 张帆   | 99    |

| 2 | mySQL         | 潘凯华 | 50    |

| 3 | SQLserver2005 | 刘智勇 | 80    |

| 4 | mySQL         | 李慧  | 50    |

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

mysql> select distinct name fromlibrary;

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

| name          |

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

| java范例大全 |

| mySQL         |

| SQLserver2005 |

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

11 用ORDER BY 关键字对查询结果排序

         mysql> select * from library orderby id desc;//倒序排列

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

| id | name          | author | price |

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

| 4 | mySQL         | 李慧  | 50    |

| 3 | SQLserver2005 | 刘智勇 | 80    |

| 2 | mySQL         | 潘凯华 | 50    |

| 1 | java范例大全  | 张帆   | 99    |

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

         mysql> select * from library orderby id asc;//正序排列

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

| id | name          | author | price |

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

| 1 | java范例大全  | 张帆   | 99    |

| 2 | mySQL         | 潘凯华 | 50    |

| 3 | SQLserver2005 | 刘智勇 | 80    |

| 4 | mySQL         | 李慧  | 50    |

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

12  用GROUP BY关键字分组查询

(1)    用GROUP BY关键字分组查询

例如：mysql> select name,price from library GROUP BY price;

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

| name          | price |

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

| mySQL         | 50    |

| SQLserver2005 | 80    |

| java范例大全  | 99   |

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

3 rows in set (0.00 sec)

 

mysql> select name,price from library GROUP BY name;

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

| name          | price |

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

| java范例大全  | 99   |

| mySQL         | 50    |

| SQLserver2005 | 80    |

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

(2)    GROUP BY 关键字与 GROU_CONCAT函数一起使用

     mysql> selectname,GROUP_CONCAT(price) from library GROUP BY name;

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

| name          |GROUP_CONCAT(price) |

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

| java范例大全  | 99                  |

| mySQL         | 50,50               |

| SQLserver2005 | 80                 |

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

（3）按多个字段进行分组

    mysql> selectid,name,price from library GROUP BY name,price;//当price字段的值相等时，再按照name字段分组

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

| id |name          | price |

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

|  1 | java范例大全  | 99    |

|  2 | mySQL         | 50   |

|  3 | SQLserver2005 | 80    |

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

13  用LIMIT限制查询结果的数量

        mysql> select * from library orderby id asc limit 2,3; //取两条数据，正序，从第三条开始

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

| id | name          | author | price |

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

| 3 | SQLserver2005 | 刘智勇 | 80    |

| 4 | mySQL         | 李慧  | 50    |

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

2 rows in set (0.00 sec)

 

mysql> select * from libraryorder by id desc limit 2,3; //取两条数据，倒序，从倒数第三条结束，只显示倒数前两个

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

| id | name         | author | price |

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

| 2 | mySQL        | 潘凯华 | 50    |

| 1 | java范例大全 | 张帆  | 99    |

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