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  • MySQL 常用运算符

    1.算数运算符

    mysql> select 1+2;

    mysql> select 2-1;

    mysql> select 2*3;

    mysql> select 5/3;

    mysql> SELECT 5 DIV 2;

    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

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

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

    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

    REF:

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

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  • 原文地址:https://www.cnblogs.com/emanlee/p/4592337.html
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