Shulou(Shulou.com)05/31 Report--

This article mainly introduces how to achieve the sentence optimization of the database, the article is very detailed, has a certain reference value, interested friends must read it!

Like statement optimization

SELECTidFROMAWHEREnamelike'%abc%'

Since "%" is used in front of abc, the query must go through the table query, unless necessary, do not add% before keywords, optimize to the following

SELECTidFROMAWHEREnamelike'abc%'

Use the where clause! = or operator optimization

Used in the where clause! = or operator, the index is discarded and a full table query is made.

For example, SQLRV SELECTidFROMAWHEREIDATION 5 is optimized to: SELECTidFROMAWHEREID > 5ORID

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