The equals operator (=) is probably the most commonly used operator in SQL. It compares the equality of two expressions. Even if you’ve only just begun your SQL journey, you’ll probably know this operator.
Ian
SQL EXISTS Operator for Beginners
In SQL, the EXISTS operator specifies a subquery to test for the existence of rows. It returns TRUE when the subquery returns one or more rows.
A subquery is a query that is nested inside another query (or even another subquery)
This article contains some basic examples of the EXISTS operator.
SQL CREATE TABLE … AS SELECT Statement
The SQL CREATE TABLE ... AS SELECT statement enables you to insert the results of a query into a new table.