mysql optimization gender optimization

Question

There are hundreds of thousands of users in the database, 90% of whom are men, sex = 1
For example: select uid member where sex =1 and xxx xx
Then this sex will scan the entire table, how to deal with it

Answer 1

In this case, the discrimination of indexing on sex is too low, and it is of little use. Let’s consider creating indexes on other fields, such as the xxx below

Answer 2

Creating a single-column index on sex can avoid full table scanning. If the efficiency is not high, you can consider establishing a joint index starting with sex and adding subsequent fields

Answer 3

Put sex in the first place in the multi-column index and process it programmatically. For example, when all of them are sex in (1, 2)