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Confused about mysql as an escaped query?

I have a table below data

select * from t;
+----+----------------+
| id | a              |
+----+----------------+
|  1 | u5929u732b     |
|  2 | \u5929\u732b   |
|  3 | \\u5929\\u732b |
+----+----------------+

The query result is used equal

select * from t where a = '\u5929\u732b';
+----+------------+
| id | a          |
+----+------------+
|  1 | u5929u732b |
+----+------------+

select * from t where a = '\\u5929\\u732b';
+----+--------------+
| id | a            |
+----+--------------+
|  2 | \u5929\u732b |
+----+--------------+

select * from t where a = '\\\\u5929\\\\u732b';
+----+----------------+
| id | a              |
+----+----------------+
|  3 | \\u5929\\u732b |
+----+----------------+

these results are the same as i expected so no problem then i used to query the result and at this time i am very confused

# as I expected
select * from t where a like '\u5929\u732b';
+----+------------+
| id | a          |
+----+------------+
|  1 | u5929u732b |
+----+------------+

# I do not understand I think it should return result of id = 2
select * from t where a like '\\u5929\\u732b';
+----+------------+
| id | a          |
+----+------------+
|  1 | u5929u732b |
+----+------------+

# I think it should return result of id = 3
select * from t where a like '\\\\u5929\\\\u732b';
+----+--------------+
| id | a            |
+----+--------------+
|  2 | \u5929\u732b |
+----+--------------+

So why is a request like

different from an equal request?

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3 answers


LIKE

escaped by default '\'. But you can change this by writing:

select * from t where a like '\\u5929\\u732b' ESCAPE '|'


Link:

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\

is an escape character in mysql. This means that the statement

select * from t where a like '\\u5929\\u732b';

equivalent to

select * from t where a like 'u5929u732b;



therefore the correct answer is correct.

So your third request ( select * from t where a like '\\\\u5929\\\\u732b';

) is a request with a request

select * from t where a like '\\u5929\\u732b;'

,

and therefore the statement that you can use to get the desired result is also correct!

+2


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You need to use wildcards with the operator like 

select * from t where a like '%5929%';
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