How MySQL uses the ESCAPE keyword

This article will introduce to you how MySQL uses the ESCAPE keyword. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

MySQL Escape

Escape represents the original semantics of the escape character. The purpose of an escape character is to start a character sequence so that escape The character sequence at the beginning of a character has different semantics than when the character sequence appears alone.

In MySQL, the escape characters start with "//m.sbmmt.com/m/faq/\". Common escape characters in programming are all valid in MySQL and will not be described or discussed here. Here, the function of the ESCAPE keyword is mainly explained through "%" and "_".

%: Match any number of characters.

_: Matches a single character.

If we want to match "%" or "_", we must use "//m.sbmmt.com/m/faq/\" to escape, as follows:

### 查询名字中带明字的用户
> SELECT * FROM user WHERE name LIKE CONCAT("%", "明", "%")

### 查询名字带有%字符的用户
> SELECT * FROM user WHERE name LIKE CONCAT("%", "\%", "%")

Usage of ESCAPE

ESCAPE keyword The main function is to specify a character to replace the function of "//m.sbmmt.com/m/faq/\".

### 查询名字带有“%”字符的用户
> SELECT * FROM user WHERE name LIKE CONCAT("%", "$%", "%") ESCAPE "$"

### 查询名字带有“_”字符的用户
> SELECT * FROM user WHERE name LIKE CONCAT("%", "a_", "%") ESCAPE "a"

It should be noted that all characters referred to by ESCAPE in the query conditions will replace the role of "//m.sbmmt.com/m/faq/\".

### 假设存在名字为 %a 和 %_ 两个的用户
> SELECT * FROM user WHERE name LIKE "a%_" ESCAPE "a"         ### %a %_ 
> SELECT * FROM user WHERE name LIKE "a%a" ESCAPE "a"         ### %a 
> SELECT * FROM user WHERE name LIKE "a%a_" ESCAPE "a"        ### %_

Related recommendations: "mysql tutorial"

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