php - Problem with Sql conditional statement

Question

A sql statement has an employee id field after group by and is put together through the group concat function. Now the business requires finding the result that the employee id is a, then the employee field must be filtered whether it only has a or contains a. Come on, how do you write this?

Answer 1

It is recommended that you briefly list the attributes of the table, otherwise the description will not be clear.
group concat is just grouping, what really plays a filtering role is the where condition

Answer 2

select * from table where id like '%a%' 

Answer 3

Use subquery, wrap it one layer and add where condition