Detailed explanation of how to query fields containing '%' in MySQL like (ESCAPE usage)

In the SQL like statement, for example

SELECT * FROM user WHERE username LIKE '%luchi%'
SELECT * FROM user WHERE username LIKE '_luchi_',

• % as a wildcard to match multiple
• _ as a wildcard

But when the field to be queried by like contains %, how do we check:

At this time, you need to specify that the '%' in the field is not used as a wildcard;
Here we need to use ESCAPE escape

test:

Here we use this table

Before escaping:

SELECT * FROM user WHERE username LIKE '%%%'; 

Here you will find that the three % signs are all treated as wildcards;

After escaping:

SELECT * FROM user WHERE username LIKE '%1%%' ESCAPE '1'; 

Query successful

Note:

• ESCAPE is followed by a character, and what is written inside is the escape character;
• Then just like the escape characters in C language, such as '\n', '\t', write this character before the % sign you need to escape;

Tips and Suggestions:

MySQL wildcards are very useful. This functionality comes at a cost, however: wildcard searches generally take longer to process than the other searches discussed previously. Here are some tips to remember when using wildcards.

• Don't overuse wildcards. If other operators can achieve the same purpose, you should use other operators.
• When you do need to use wildcards, don't use them at the beginning of a search pattern unless absolutely necessary. Placing the wildcard at the beginning of the search pattern is the slowest search.
• Note carefully the placement of the wildcard characters. If placed in the wrong place, it may not return the expected number.

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