What is the UNION operator in mysql?
The MySQL UNION operator is used to combine the results of two or more SELECT statements into a result set.
Multiple SELECT statements will delete duplicate data.
UNION operator syntax:
SELECT column_name(s) FROM table1 UNION SELECT column_name(s) FROM table2;
Note: The column name in the UNION result set is always equal to the first SELECT in UNION Column names in statements.
Usage example: Select all different countries (only different values) from the "Websites" and "app" tables
SELECT country FROM Websites UNION SELECT country FROM app ORDER BY country;
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