Mysql index operations

1. Create a single INDEX for the TABLE. alter table table_name add index indexName (colname );
Create multiple-column index alter table table_name add index indexName1_indexName2 (colname1, colname2 );
This method of joint creation of multiple columns is more efficient than creating multiple single-column indexes separately, because this method will actually use indexes indexName1, indexName2, when querying Multiple Single-Column modes, only the strictest one of them will be used, so it cannot achieve better efficiency. 2. Delete the index alter table table_name drop index indexName; the index will cause the query operation time to be added or modified, so it is best not to use the index if there is no common query.
Author: jias_je