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The role of the escape

Escape is used for wildcard escape

For example, if you want to search for a string containing a wildcard character, it will be interpreted as a wildcard character, rather than a normal character, and will definitely not be able to find it

The first character immediately after the escape character is treated as a normal character rather than a wildcard character

The escape usage

Let’s say there are five pieces of data, as shown above

Query Example 1

Let’s say we want to query for % in the username field

In the right mind, we could do this

The wrong sample

select * from tablename where username like '%%%'
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The idea is that the first and third % are wildcards, and the second % is a normal character, but written this way, the computer doesn’t know, and it will treat all % as wildcards

The result of this query is not what we need

The second % can then be identified with escape

The correct sample

select * from tablename where username like '%#%%' escape '#'
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Escape specifies that the first character after the # character is considered a normal character

Query Example 2

Select * from username where username = ‘username’;

select * from tablename where username like '%#[%' escape '#'
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