MySQL 运算符

原文：http://www.jb51.net/article/25657.htm

我一贯秉承着一点：通过自己的双手真实的操作一遍之后的信息是最可靠的，所以在您参考这个小文儿的时候请不要只是“看”，单纯的瞧一瞧是得不到真知滴~~~

座右铭：纸上得来终觉浅，绝知此事要躬行！

1.算数运算符

加

mysql> select 1+2;

减

mysql> select 2-1;

乘

mysql> select 2*3;

除

mysql> select 5/3;

商

mysql> SELECT 5 DIV 2;

模

mysql> select 5%2,mod(5,2);

2.比较运算符

等于

mysql> select 1=0,1=1,null=null;

不等于

mysql> select 1<>0,1<>1,null<>null;

安全等于

mysql> select 1<=>1,2<=>0,0<=>0,null<=>null;

小于

mysql> select ‘a’<’b’,’a’<’a’,’a’<’c’,1<2;

小于等于

mysql> select ‘bdf’<=’b’,’b’<=’b’,0<1;

大于

mysql> select ‘a’>’b’,’abc’>’a’,1>0;

大于等于

mysql> select ‘a’>=’b’,’abc’>=’a’,1>=0,1>=1;

BETWEEN

mysql> select 10 between 10 and 20, 9 between 10 and 20;

IN

mysql> select 1 in (1,2,3), ‘t’ in (‘t’,’a’,’b’,’l’,’e’), 0 in (1,2);

IS NULL

mysql> select 0 is null,null is null;

IS NOT NULL

mysql> select 0 is not null, null is not null;

LIKE

mysql> select 123456 like ‘123%’, 123456 like ‘%123%’, 123456 like ‘%321%’;

REGEXP

mysql> select ‘abcdef’ regexp ‘ab’, ‘abcdefg’ regexp ‘k’;

3.逻辑运算符

非

mysql> select not 0, not 1, not null;

mysql> select ! 0, ! 1, ! null;

与

mysql> select (1 and 1), (0 and 1), (3 and 1), (1 and null);

mysql> select (1 && 1), (0 && 1), (3 && 1), (1 && null);

或

mysql> select (1 or 0), (0 or 0), (1 or null), (1 or 1), (null or null);

mysql> select (1 || 0), (0 || 0), (1 || null), (1 || 1), (null || null);

异或

mysql> select (1 xor 1), (0 xor 0), (1 xor 0), (0 xor 1), (null xor 1);

mysql> select (1 ^ 1), (0 ^ 0), (1 ^ 0), (0 ^ 1), (null ^ 1);

4.位运算符

位与

mysql> select 2&3;

mysql> select 2&3&4;

位或

mysql> select 2|3;

位异或

mysql> select 2^3;

位取反

mysql> select ~1,~18446744073709551614;

位右移

mysql> select 100>>3;

位左移

mysql> select 100<<3;

5.运算符优先级顺序

最高优先级 :=

1 ||, OR, XOR

2 &&, AND

3 BETWEEN, CASE, WHEN, THEN, ELSE

4 =, <=>, >=, >, <=, <, <>, !=, IS, LIKE, REGEXP, IN

5 |

6 &

7 <<, >>

8 -, +

9 *, /, DIV, %, MOD

10 ^

11 - (unary minus), ~ (unary bit inversion)

12 !, NOT

最低优先级 BINARY, COLLATE

好运。

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