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Oracle Tutorials - Use Subqueries with the EXISTS Operator
(Continued from previous topic...)
How To Use Subqueries with the EXISTS Operator?
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
2 WHERE EXISTS (
3 SELECT * FROM departments d
4 WHERE e.department_id = d.department_id
5 AND d.location_id = 1700
Lex De Haan
(Continued on next topic...)
- What Is a SELECT Query Statement?
- How To Select All Columns of All Rows from a Table?
- How To Select Some Columns from a Table?
- How To Select Some Rows from a Table?
- How To Sort the Query Output?
- Can the Query Output Be Sorted by Multiple Columns?
- How To Sort Query Output in Descending Order?
- How To Use SELECT Statement to Count the Number of Rows?
- Can SELECT Statements Be Used on Views?
- How To Filter Out Duplications in Returning Rows?
- What Are Group Functions?
- How To Use Group Functions in the SELECT Clause?
- Can Group Functions Be Mixed with Non-group Selection Fields?
- How To Divide Query Output into Groups?
- How To Apply Filtering Criteria at Group Level?
- How To Count Duplicated Values in a Column?
- Can Multiple Columns Be Used in GROUP BY?
- Can Group Functions Be Used in the ORDER BY Clause?
- How To Join Two Tables in a Single Query?
- How To Write a Query with an Inner Join?
- How To Define and Use Table Alias Names?
- How To Write a Query with a Left Outer Join?
- How To Write a Query with a Right Outer Join?
- How To Write a Query with a Full Outer Join?
- How To Write an Inner Join with the WHERE Clause?
- How To Write a Left Outer Join with the WHERE Clause?
- How To Name Query Output Columns?
- What Is a Subquery?
- How To Use Subqueries with the IN Operator?
- How To Use Subqueries with the EXISTS Operator?
- How To Use Subqueries in the FROM Clause?
- How To Count Groups Returned with the GROUP BY Clause?
- How To Return Top 5 Rows?