SQLite INTERSECT operator is used to combine the results of two or more SELECT statements by returning only the rows that are common to all of them. In other words, the INTERSECT operator returns the intersection of the result sets produced by each SELECT statement.
Syntax
The syntax for using the INTERSECT operator is as follows:
SELECT column1, column2, ... FROM table1 INTERSECT SELECT column1, column2, ... FROM table2;
In this syntax, the columns selected in each SELECT statement must match in number and data type. Also, the tables involved in the SELECT statements must have the same number of columns, and the columns must be in the same order.
The INTERSECT operator works by comparing the result sets produced by each SELECT statement and returning only the rows that exist in all of them. This means that the result set produced by the INTERSECT operator will have the same number of columns as the SELECT statements, and the data in each column will be the same data type as the corresponding columns in the SELECT statements.
It is important to note that the INTERSECT operator only returns distinct rows. This means that if there are duplicate rows in either of the SELECT statements, they will be eliminated from the result set produced by the INTERSECT operator.
In conclusion, the SQLite INTERSECT operator is a powerful tool that allows developers to combine the results of multiple SELECT statements and retrieve only the rows that are common to all of them. This can be particularly useful in scenarios where you need to find the intersection of two or more data sets.