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This article will explain in detail what the mysql index specification is, and the editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

1. It is recommended that the index of a single table be controlled within 5.

2. The number of combined index fields is not recommended to exceed 5.

3. Join forbids more than three tables.

For fields that require join, the data type must be absolutely consistent.

4. It is strictly forbidden to be left fuzzy or full fuzzy, if you need to solve it with a search engine.

5. If there is an orderby scenario, please pay attention to the ordering of the index.

Example

1) there is at most one matching row (primary key or unique index) in a single consts table, and the data can be read in the optimization phase. 2) ref refers to the use of a normal normal index. 3) range searches the range of the index. Counterexample: the result of explain table, type=index, index physical file full scan, the speed is very slow, this index level is lower than range, and is negligible compared with full table scan. This is the end of this article on "what is the mysql index specification". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it out for more people to see.

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