every derived table must have its own alias

Question

i am running this query on mysql

 SELECT ID FROM (SELECT ID, msisdn FROM (SELECT * FROM TT2));

and it is giving this error:

Every derived table must have its own alias.

what is wrong ?

Answer 1

I think it's asking you to do this:

SELECT ID FROM (SELECT ID, msisdn FROM (SELECT * FROM TT2) as myalias) as anotheralias;

But why would you write this query in the first place?

Answer 2

Every derived table must indeed have an alias.

SELECT ID FROM (
    SELECT ID, msisdn FROM (
        SELECT * FROM TT2
    ) AS T
) AS T

In your case, the entire query could be replaced with:

SELECT ID FROM TT2