mysql索引操作_MySQL
bitsCN.com
1 为表创建索单列索引 ALTER TABLE table_name ADD INDEX indexName (colname);
创建多列索引 ALTER TABLE table_name ADD INDEX indexName1_indexName2 (colname1,colname2);
这种联合创建多列的方式比分别创建多个单列索引的效率高,因为这种方式在查询时会真正联合使用索引 indexName1,indexName2,而多个单列的模式查询时只会用其中最严格的一个,达不到更好的高效 2 删除索引 ALTER TABLE table_name DROP INDEX indexName; 索引会引起添加、修改的查询操作时间、所以在没有常用查询的情况下最好不要用,取消索引
作者 jias_je bitsCN.com

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