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This article introduces the knowledge of "how to check whether an index is used in SQL statements". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

How do I check whether an index is used in a SQL statement?

Use the "EXPLAIN sql statement" for debugging to view possible_keys or key

Possible_keys: indexes that may be applied

Key: the index actually used

Under what circumstances will the index be ignored

Leading LIKE statement

The leading fuzzy query is not valid (such as like'% XX' or like'% XX%')

/ / effective

Explain select * from cartoon where `name` like 'there is a grown-up in the family%'

/ / does not take effect

Explain select * from cartoon where `name` like'% 555%'

"or" condition

"in" condition

"" is not equal to judgment.

"between" range condition, you can use where xx > 1 and xx

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