Heim >Datenbank >MySQL-Tutorial >mysql运算符大全、优先级及实例讲解
1、加
<code class="language-sql">mysql> select 1+2; +-----+ | 1+2 | +-----+ | 3 | +-----+</code>
2、减
<code class="language-sql">mysql> select 1-2; +-----+ | 1-2 | +-----+ | -1 | +-----+</code>
3、乘
<code class="language-sql">mysql> select 2*3; +-----+ | 2*3 | +-----+ | 6 | +-----+</code>
4、除
<code class="language-sql">mysql> select 2/3; +--------+ | 2/3 | +--------+ | 0.6667 | +--------+</code>
5、商
<code class="language-sql">mysql> select 10 DIV 4; +----------+ | 10 DIV 4 | +----------+ | 2 | +----------+</code>
6、取余
<code class="language-sql">mysql> select 10 MOD 4; +----------+ | 10 MOD 4 | +----------+ | 2 | +----------+</code>
1、等于
<code class="language-sql">mysql> select 2=3; +-----+ | 2=3 | +-----+ | 0 | +-----+ mysql> select NULL = NULL; +-------------+ | NULL = NULL | +-------------+ | NULL | +-------------+</code>
2、不等于
<code class="language-sql">mysql> select 23; +------+ | 23 | +------+ | 1 | +------+</code>
3、安全等于
与“=”的区别在于当两个操作码均为NULL时,其所得值为1而不为NULL,而当一个操作码为NULL时,其所得值为0而不为NULL。
<code class="language-sql">mysql> select 23; +-------+ | 23 | +-------+ | 0 | +-------+ mysql> select null=null; +-----------+ | null=null | +-----------+ | NULL | +-----------+ mysql> select nullnull; +-------------+ | nullnull | +-------------+ | 1 | +-------------+</code>
4、小于
<code class="language-sql">mysql> select 2</code>
5、小于等于
<code class="language-sql">mysql> select 2</code>
6、大于
<code class="language-sql">mysql> select 2>3; +-----+ | 2>3 | +-----+ | 0 | +-----+</code>
7、大于等于
<code class="language-sql">mysql> select 2>=3; +------+ | 2>=3 | +------+ | 0 | +------+</code>
8、BETWEEN
<code class="language-sql">mysql> select 5 between 1 and 10; +--------------------+ | 5 between 1 and 10 | +--------------------+ | 1 | +--------------------+</code>
9、IN
<code class="language-sql">mysql> select 5 in (1,2,3,4,5); +------------------+ | 5 in (1,2,3,4,5) | +------------------+ | 1 | +------------------+</code>
10、NOT IN
<code class="language-sql">mysql> select 5 not in (1,2,3,4,5); +----------------------+ | 5 not in (1,2,3,4,5) | +----------------------+ | 0 | +----------------------+</code>
11、IS NULL
<code class="language-sql">mysql> select null is NULL; +--------------+ | null is NULL | +--------------+ | 1 | +--------------+ mysql> select 'a' is NULL; +-------------+ | 'a' is NULL | +-------------+ | 0 | +-------------+</code>
12、IS NOT NULL
<code class="language-sql">mysql> select null IS NOT NULL; +------------------+ | null IS NOT NULL | +------------------+ | 0 | +------------------+ mysql> select 'a' IS NOT NULL; +-----------------+ | 'a' IS NOT NULL | +-----------------+ | 1 | +-----------------+</code>
13、LIKE
<code class="language-sql">mysql> select '12345' like '12%'; +--------------------+ | '12345' like '12%' | +--------------------+ | 1 | +--------------------+ mysql> select '12345' like '12_'; +--------------------+ | '12345' like '12_' | +--------------------+ | 0 | +--------------------+</code>
14、REGEXP
<code class="language-sql">mysql> select 'beijing' REGEXP 'jing'; +-------------------------+ | 'beijing' REGEXP 'jing' | +-------------------------+ | 1 | +-------------------------+ mysql> select 'beijing' REGEXP 'xi'; +-----------------------+ | 'beijing' REGEXP 'xi' | +-----------------------+ | 0 | +-----------------------+</code>
1、与
<code class="language-sql">mysql> select 2 and 0; +---------+ | 2 and 0 | +---------+ | 0 | +---------+ mysql> select 2 and 1; +---------+ | 2 and 1 | +---------+ | 1 | +---------+</code>
2、或
<code class="language-sql">mysql> select 2 or 0; +--------+ | 2 or 0 | +--------+ | 1 | +--------+ mysql> select 2 or 1; +--------+ | 2 or 1 | +--------+ | 1 | +--------+ mysql> select 0 or 0; +--------+ | 0 or 0 | +--------+ | 0 | +--------+ mysql> select 1 || 0; +--------+ | 1 || 0 | +--------+ | 1 | +--------+</code>
3、非
<code class="language-sql">mysql> select not 1; +-------+ | not 1 | +-------+ | 0 | +-------+ mysql> select !0; +----+ | !0 | +----+ | 1 | +----+</code>
4、异或
<code class="language-sql">mysql> select 1 xor 1; +---------+ | 1 xor 1 | +---------+ | 0 | +---------+ mysql> select 0 xor 0; +---------+ | 0 xor 0 | +---------+ | 0 | +---------+ mysql> select 1 xor 0; +---------+ | 1 xor 0 | +---------+ | 1 | +---------+ mysql> select null or 1; +-----------+ | null or 1 | +-----------+ | 1 | +-----------+ mysql> select 1 ^ 0; +-------+ | 1 ^ 0 | +-------+ | 1 | +-------+</code>
1、按位与
<code class="language-sql">mysql> select 3&5; +-----+ | 3&5 | +-----+ | 1 | +-----+</code>
2、按位或
<code class="language-sql">mysql> select 3|5; +-----+ | 3|5 | +-----+ | 7 | +-----+</code>
3、按位异或
<code class="language-sql">mysql> select 3^5; +-----+ | 3^5 | +-----+ | 6 | +-----+</code>
4、按位取反
<code class="language-sql">mysql> select ~18446744073709551612; +-----------------------+ | ~18446744073709551612 | +-----------------------+ | 3 | +-----------------------+</code>
5、按位右移
<code class="language-sql">mysql> select 3>>1; +------+ | 3>>1 | +------+ | 1 | +------+</code>
6、按位左移
<code class="language-sql">mysql> select 3</code>
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