In a subquery, you can use group by, but your syntax is incorrect.
Wherever expressions are allowed, subqueries can be used in SELECT, INSERT, UPDATE, and DELETE statements. A subquery can be used as a table expression in the FROM clause or as one of the column expressions in a SELECT list.
An example of a typical correlated subquery is shown below. In this case, the goal is to locate all employees with salaries that are higher than the average for their department. WHERE salary >... SELECT employee number, name FROM employees emp The inner query in the above nested query must be re-executed for each employee.
It is the usage of a SELECT statement inside one of the clauses of another SELECT statement in a more formal sense. A subquery can, in reality, be contained within another subquery, which is contained within another subquery, and so on.
The subquery can be nested inside another subquery or inside a SELECT, INSERT, UPDATE, or DELETE statement. A subquery is frequently added to another SQL SELECT statement's WHERE Clause. You can use comparison operators like >,, or = to make a comparison.