What is the problem with the following sql? The mysql command console has been running for one night but no results are produced.

Question

select projname from project where id in (select proj from assign  where type_id  in (50,55) group by proj);

Answer 1

If you don't know the error, you can split the statement into multiple statements and execute them in the order you want. You don’t know what the table structure is like. If you ask others to help you find errors, isn’t it just asking others to guess?