The INTERSECT operator in SQL is used to retrieve the common records or rows from two or more SELECT statements.

The INTERSECT operator compares the result sets of two or more SELECT statements and returns only the rows that appear in all the result sets. This can be useful when you need to find the common elements in multiple sets of data.

For example, let’s say you have two tables: “students” and “teachers”. If you want to find the names of students who are also teachers, you can use the INTERSECT operator to compare the results of two SELECT statements:

SELECT name FROM students
INTERSECT
SELECT name FROM teachers;

This will return the names of all students who are also teachers.

The INTERSECT operator can also be used with more than two SELECT statements, as long as all the SELECT statements have the same number of columns and data types.