SQL EXISTS

The SQL EXISTS Operator

The EXISTS operator evaluates whether any records exist in a subquery.

It returns TRUE if the subquery yields one or more records.

SELECT column_name(s)
FROM table_name
WHERE EXISTS
(SELECT column_name FROM table_name WHERE condition);

Here is a segment extracted from the “Products” table within the Northwind sample database:

And here is an excerpt from the “Suppliers” table:

This SQL statement returns TRUE and displays the suppliers who offer a product priced below 20.

SELECT SupplierName
FROM Suppliers
WHERE EXISTS (SELECT ProductName FROM Products WHERE Products.SupplierID = Suppliers.supplierID AND Price < 20);

This SQL statement returns TRUE and presents the suppliers offering a product priced at 22.

SELECT SupplierName
FROM Suppliers
WHERE EXISTS (SELECT ProductName FROM Products WHERE Products.SupplierID = Suppliers.supplierID AND Price = 22);