How to use exists in SQL?

Question

Can anyone tell me how to use exists in SQL?

Answer 1

EXISTS operator is used to checking whether the records exist in the subquery and returns true if exists.

Here is the syntax to use EXISTS operator in SQL:

SELECT column_list
FROM Table_Name
WHERE EXISTS
(SELECT Column_Name FROM Table_Name  WHERE condition(s));

Here is the statement to find the names of customers who placed a minimum of one order (using EXISTS operator) :

SELECT Customer_Name

FROM Customers

WHERE EXISTS (SELECT *

                                FROM Orders

                                WHERE Customers.customer_id = Orders.customer_id)

You can check out this SQL tutorial to learn using EXIST operators with examples.