mysql - 索引过滤性不好是由什么原因引起的，应该怎么解决

Question

索引过滤性不好是由什么原因引起的，应该怎么解决

Answer 1

That is, the column you indexed does not change much and has few distributed values, such as gender or order status. There is no need to build an index. It will not improve query efficiency but increase the insertion burden