Use Subqueries with the EXISTS Operator in Oracle


How To Use Subqueries with the EXISTS Operator in Oracle?



A subquery can be used with the EXISTS operator as "EXISTS (subquery)", which returns true if the subquery returns one or more rows. The following statement is a good example of "EXISTS (subquery)". It returns rows from employees table that there are rows existing in the departments table linked to the employees table with location_id = 1700.

SQL> SELECT first_name, last_name FROM employees e 
  3    SELECT * FROM departments d 
  4    WHERE e.department_id = d.department_id
  5    AND d.location_id = 1700
  6  );
-------------------- -------------------------
Steven               King
Neena                Kochhar
Lex                  De Haan
Nancy                Greenberg
Daniel               Faviet
John                 Chen
Ismael               Sciarra


Use Subqueries in the FROM Clause in Oracle

Use Subqueries with the IN Operator in Oracle

Understanding SQL SELECT Query Statements in Oracle

⇑⇑ Oracle Database Tutorials

2019-09-27, 1660🔥, 0💬