SQL EXISTS Keyword Usage and Examples

SQL Keyword Reference

EXISTS

The EXISTS command tests if any records exist in the subquery, and returns true if the subquery returns one or more records.

The following SQL lists the product prices below2Supplier with product prices below

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

The following SQL lists the product prices equal to22Supplier:

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

SQL Keyword Reference