MySQL学习足迹记录05--数据过滤--AND,OR,NOT,IN

                             过滤数据所用到的表格数据，详见MySQL学习足迹记录02

1.AND操作符

   * 检索匹配满足所有给定条件的行

  eg:

   mysql> SELECT prod_id,prod_price,prod_name FROM products WHERE 

    -> vend_id =1003 AND prod_price<=10;

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

| prod_id | prod_price | prod_name      |

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

| FB      |      10.00 | Bird seed      |

| FC      |       2.50 | Carrots        |

| SLING   |       4.49 | Sling          |

| TNT1    |       2.50 | TNT (1 stick)  |

| TNT2    |      10.00 | TNT (5 sticks) |

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

5 rows in set (0.00 sec)

2.OR操作符

  *检索匹配满足给定任一条件的行

  eg:

 mysql> SELECT prod_name,prod_price FROM products 

          -> WHERE vend_id=1002 or vend_id=1003;

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

| prod_name      | prod_price |

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

| Detonator      |      13.00 |

| Bird seed      |      10.00 |

| Carrots        |       2.50 |

| Fuses          |       3.42 |

| Oil can        |       8.99 |

| Safe           |      50.00 |

| Sling          |       4.49 |

| TNT (1 stick)  |       2.50 |

| TNT (5 sticks) |      10.00 |

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

9 rows in set (0.01 sec)

3.计算次序

  *WHERE可以包含任意数目的AND和OR操作符。

  eg:

   mysql> SELECT prod_name,prod_price FROM products 

            -> WHERE vend_id=1002 OR vend_id=1003 AND prod_price>=10;

                                     #在处理OR操作符之前，AND操作符会被优先处理

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

| prod_name      | prod_price |

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

| Detonator      |      13.00 |

| Bird seed      |      10.00 |

| Fuses          |       3.42 |

| Oil can        |       8.99 |

| Safe           |      50.00 |

| TNT (5 sticks) |      10.00 |

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

6 rows in set (0.00 sec)

4.用（）改变计算次序

  eg:

  mysql> SELECT prod_name,prod_price FROM products

           -> WHERE (vend_id=1002 OR vend_id=1003) AND prod_price >= 10;

                                       #先计算OR，再计算AND

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

| prod_name      | prod_price |

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

| Detonator      |      13.00 |

| Bird seed      |      10.00 |

| Safe           |      50.00 |

| TNT (5 sticks) |      10.00 |

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

4 rows in set (0.00 sec)

5.IN操作符

  *用来指定条件范围

 eg:

mysql> SELECT prod_name,prod_price FROM products

         -> WHERE vend_id IN (1002,1003)

         -> ORDER BY prod_name;

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

| prod_name      | prod_price |

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

| Bird seed      |      10.00 |

| Carrots        |       2.50 |

| Detonator      |      13.00 |

| Fuses          |       3.42 |

| Oil can        |       8.99 |

| Safe           |      50.00 |

| Sling          |       4.49 |

| TNT (1 stick)  |       2.50 |

| TNT (5 sticks) |      10.00 |

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

9 rows in set (0.00 sec)

上面的语句等效于：

mysql> SELECT prod_name,prod_price FROM products 

         -> WHERE vend_id =1002 OR vend_id = 1003

         -> ORDER BY prod_name;

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

| prod_name      | prod_price |

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

| Bird seed      |      10.00 |

| Carrots        |       2.50 |

| Detonator      |      13.00 |

| Fuses          |       3.42 |

| Oil can        |       8.99 |

| Safe           |      50.00 |

| Sling          |       4.49 |

| TNT (1 stick)  |       2.50 |

| TNT (5 sticks) |      10.00 |

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

9 rows in set (0.00 sec)

6.NOT操作符

  *否定它之后所跟的任何条件

  eg:

   mysql> SELECT vend_id,prod_price FROM products

            -> WHERE vend_id NOT IN (1002,1003)

           -> ORDER BY prod_name;

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

| vend_id | prod_price |

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

|    1001 |       5.99 |

|    1001 |       9.99 |

|    1001 |      14.99 |

|    1005 |      35.00 |

|    1005 |      55.00 |

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

5 rows in set (0.00 sec)