SQLite UNION operator is a powerful feature that allows you to combine two or more SELECT statements into a single result set. The UNION operator is used to merge the results of two or more SELECT statements into a single result set.
The syntax for using the UNION operator is quite simple. You start with the SELECT statement that you want to use to create the result set, and then you add the UNION keyword followed by another SELECT statement. You can use as many SELECT statements as you want, as long as they all have the same number of columns and data types.
Syntax
Here is the basic syntax for using the UNION operator in SQLite:
SELECT column1, column2, ... columnN FROM table1 UNION SELECT column1, column2, ... columnN FROM table2;
In this syntax, the UNION operator is used to combine the results of two SELECT statements that retrieve data from two different tables. The columns specified in both SELECT statements should be identical and in the same order. The result set of the UNION operator will only include unique rows, so duplicates are automatically removed.
You can also use the UNION operator with other operators like UNION ALL, INTERSECT, and EXCEPT. The UNION ALL operator works like the UNION operator but does not remove duplicates. The INTERSECT operator retrieves only the rows that are common to both SELECT statements, while the EXCEPT operator retrieves only the rows that are unique to the first SELECT statement.
In conclusion, the SQLite UNION operator is a powerful tool that allows you to combine the results of two or more SELECT statements into a single result set. By using the UNION operator, you can create more complex and sophisticated queries that can help you to retrieve and manipulate data more efficiently.