MySQL学习足迹记录05--数据过滤--AND,OR,NOT,IN_MySQL

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MySQL学习足迹记录05--数据过滤--AND,OR,NOT,IN

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
 
 
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)
 
 
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