MySQL中的运算符使用实例展示 |
|
本文标签：运算符 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 。 -- The End -- |
