How could I improve the performance of this query?

Question

Consider that you have a MySQL table named “user” with millions of rows that have the following structure, and doesn't have any index.

TABLE:  user_id (PK) email name signup_date

We want to execute the following query:

SELECT user_id
FROM user
WHERE email=’email@bolidea.com’ AND name=’Olivier Cabanes’ 

1. How does MySQL handle that query in term of speed?
2. How can you improve the performance of that query?

Answer 1

您需要在电子邮件和名称上建立索引，否则它将需要遍历表格的每一行，而且速度非常慢...

Answer 2

Put an index on either email or name. No need for an index on both, since both are basically unique on their own