Question

The following sql query is not working.

select UserName 
from [User] 
where UserID Like 
      ( select UserID 
        from UserRoles 
        where RoleID =
              ( select RoleID 
                from Roles 
                where RoleName='Manager'
              )
      )

Here we are working with 3 tables User, UserRoles, Roles. It shows the error as follows

Subquery returned more than 1 value. This is not permitted when the
subquery follows =, !=, <, <= , >, >= or when the subquery is used as
an expression.

Answer 1

The reason for the error is that a subquery is returning more than one row.

When you have a condition like a = b or one with a LIKE b, both sides should be one item. If either side is a subquery, care should be taken that the subquery always returns either 0 or 1 row (and never more than one).

You can rewrite with Joins or changing the LIKE and the = to IN:

select UserName 
from [User] 
where UserID IN                          --- LIKE replaced
      ( select UserID 
        from UserRoles 
        where RoleID IN                  --- equality (=) replaced
              ( select RoleID 
                from Roles 
                where RoleName = 'Manager'
              )
      ) ;