mysql any运算符_MySQL 运算符
MySQL 運(yùn)算符
本章節(jié)我們主要介紹 MySQL 的運(yùn)算符及運(yùn)算符的優(yōu)先級(jí)。
MySQL 主要有以下幾種運(yùn)算符:
算術(shù)運(yùn)算符
比較運(yùn)算符
邏輯運(yùn)算符
位運(yùn)算符
算術(shù)運(yùn)算符
MySQL 支持的算術(shù)運(yùn)算符包括:
運(yùn)算符
作用
+
加法
-
減法
*
乘法
/ 或 DIV
除法
% 或 MOD
取余
在除法運(yùn)算和模運(yùn)算中,如果除數(shù)為0,將是非法除數(shù),返回結(jié)果為NULL。
1、加
mysql> select 1+2;
+-----+
| 1+2 |
+-----+
| 3 |
+-----+
2、減
mysql> select 1-2;
+-----+
| 1-2 |
+-----+
| -1 |
+-----+
3、乘
mysql> select 2*3;
+-----+
| 2*3 |
+-----+
| 6 |
+-----+
4、除
mysql> select 2/3;
+--------+
| 2/3 |
+--------+
| 0.6667 |
+--------+
5、商
mysql> select 10 DIV 4;
+----------+
| 10 DIV 4 |
+----------+
| 2 |
+----------+
6、取余
mysql> select 10 MOD 4;
+----------+
| 10 MOD 4 |
+----------+
| 2 |
+----------+
比較運(yùn)算符
SELECT 語(yǔ)句中的條件語(yǔ)句經(jīng)常要使用比較運(yùn)算符。通過(guò)這些比較運(yùn)算符,可以判斷表中的哪些記錄是符合條件的。比較結(jié)果為真,則返回 1,為假則返回 0,比較結(jié)果不確定則返回 NULL。
符號(hào)
描述
備注
=
等于
<>, !=
不等于
>
大于
<
小于
<=
小于等于
>=
大于等于
BETWEEN
在兩值之間
>=min&&<=max
NOT BETWEEN
不在兩值之間
IN
在集合中
NOT IN
不在集合中
<=>
嚴(yán)格比較兩個(gè)NULL值是否相等
兩個(gè)操作碼均為NULL時(shí),其所得值為1;而當(dāng)一個(gè)操作碼為NULL時(shí),其所得值為0
LIKE
模糊匹配
REGEXP 或 RLIKE
正則式匹配
IS NULL
為空
IS NOT NULL
不為空
1、等于
mysql> select 2=3;
+-----+
| 2=3 |
+-----+
| 0 |
+-----+
mysql> select NULL = NULL;
+-------------+
| NULL = NULL |
+-------------+
| NULL |
+-------------+
2、不等于
mysql> select 2<>3;
+------+
| 2<>3 |
+------+
| 1 |
+------+
3、安全等于
與 = 的區(qū)別在于當(dāng)兩個(gè)操作碼均為 NULL 時(shí),其所得值為 1 而不為 NULL,而當(dāng)一個(gè)操作碼為 NULL 時(shí),其所得值為 0而不為 NULL。
mysql> select 2<=>3;
+-------+
| 2<=>3 |
+-------+
| 0 |
+-------+
mysql> select null=null;
+-----------+
| null=null |
+-----------+
| NULL |
+-----------+
mysql> select null<=>null;
+-------------+
| null<=>null |
+-------------+
| 1 |
+-------------+
4、小于
mysql> select 2<3;
+-----+
| 2<3 |
+-----+
| 1 |
+-----+
5、小于等于
mysql> select 2<=3;
+------+
| 2<=3 |
+------+
| 1 |
+------+
6、大于
mysql> select 2>3;
+-----+
| 2>3 |
+-----+
| 0 |
+-----+
7、大于等于
mysql> select 2>=3;
+------+
| 2>=3 |
+------+
| 0 |
+------+
8、BETWEEN
mysql> select 5 between 1 and 10;
+--------------------+
| 5 between 1 and 10 |
+--------------------+
| 1 |
+--------------------+
9、IN
mysql> select 5 in (1,2,3,4,5);
+------------------+
| 5 in (1,2,3,4,5) |
+------------------+
| 1 |
+------------------+
10、NOT IN
mysql> select 5 not in (1,2,3,4,5);
+----------------------+
| 5 not in (1,2,3,4,5) |
+----------------------+
| 0 |
+----------------------+
11、IS NULL
mysql> select null is NULL;
+--------------+
| null is NULL |
+--------------+
| 1 |
+--------------+
mysql> select 'a' is NULL;
+-------------+
| 'a' is NULL |
+-------------+
| 0 |
+-------------+
12、IS NOT NULL
mysql> select null IS NOT NULL;
+------------------+
| null IS NOT NULL |
+------------------+
| 0 |
+------------------+
mysql> select 'a' IS NOT NULL;
+-----------------+
| 'a' IS NOT NULL |
+-----------------+
| 1 |
+-----------------+
13、LIKE
mysql> select '12345' like '12%';
+--------------------+
| '12345' like '12%' |
+--------------------+
| 1 |
+--------------------+
mysql> select '12345' like '12_';
+--------------------+
| '12345' like '12_' |
+--------------------+
| 0 |
+--------------------+
14、REGEXP
mysql> select 'beijing' REGEXP 'jing';
+-------------------------+
| 'beijing' REGEXP 'jing' |
+-------------------------+
| 1 |
+-------------------------+
mysql> select 'beijing' REGEXP 'xi';
+-----------------------+
| 'beijing' REGEXP 'xi' |
+-----------------------+
| 0 |
+-----------------------+
邏輯運(yùn)算符
邏輯運(yùn)算符用來(lái)判斷表達(dá)式的真假。如果表達(dá)式是真,結(jié)果返回 1。如果表達(dá)式是假,結(jié)果返回 0。
運(yùn)算符號(hào)
作用
NOT 或 !
邏輯非
AND
邏輯與
OR
邏輯或
XOR
邏輯異或
1、與
mysql> select 2 and 0;
+---------+
| 2 and 0 |
+---------+
| 0 |
+---------+
mysql> select 2 and 1;
+---------+
| 2 and 1 |
+---------+
| 1 |
+---------+
2、或
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 |
+--------+
3、非
mysql> select not 1;
+-------+
| not 1 |
+-------+
| 0 |
+-------+
mysql> select !0;
+----+
| !0 |
+----+
| 1 |
+----+
4、異或
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 |
+-------+
位運(yùn)算符
位運(yùn)算符是在二進(jìn)制數(shù)上進(jìn)行計(jì)算的運(yùn)算符。位運(yùn)算會(huì)先將操作數(shù)變成二進(jìn)制數(shù),進(jìn)行位運(yùn)算。然后再將計(jì)算結(jié)果從二進(jìn)制數(shù)變回十進(jìn)制數(shù)。
運(yùn)算符號(hào)
作用
&
按位與
|
按位或
^
按位異或
!
取反
<<
左移
>>
右移
1、按位與
mysql> select 3&5;
+-----+
| 3&5 |
+-----+
| 1 |
+-----+
2、按位或
mysql> select 3|5;
+-----+
| 3|5 |
+-----+
| 7 |
+-----+
3、按位異或
mysql> select 3^5;
+-----+
| 3^5 |
+-----+
| 6 |
+-----+
4、按位取反
mysql> select ~18446744073709551612;
+-----------------------+
| ~18446744073709551612 |
+-----------------------+
| 3 |
+-----------------------+
5、按位右移
mysql> select 3>>1;
+------+
| 3>>1 |
+------+
| 1 |
+------+
6、按位左移
mysql> select 3<<1;
+------+
| 3<<1 |
+------+
| 6 |
+------+
運(yùn)算符優(yōu)先級(jí)
最低優(yōu)先級(jí)為: :=。
最高優(yōu)先級(jí)為: !、BINARY、 COLLATE。
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