How To Use Subqueries with the IN Operator

Q

How To Use Subqueries with the IN Operator? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements

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A

A subquery can be used with the IN operator as "expression IN (subquery)". The subquery should return a single column with one or more rows to form a list of values to be used by the IN operation. The following tutorial exercise shows you how to use a subquery with the IN operator:

SQL> SELECT first_name, last_name FROM employees 
  2  WHERE department_id IN (
  3    SELECT department_id FROM departments 
  4    WHERE location_id = 1700
  5  );

FIRST_NAME           LAST_NAME
-------------------- -------------------------
Steven               King
Neena                Kochhar
Lex                  De Haan
Nancy                Greenberg
Daniel               Faviet
John                 Chen
Ismael               Sciarra
......

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