Explain the difference between UNION and UNION ALL

UNION:

• Combines the results of two or more SELECT queries.
• Removes duplicates from the combined result.

Syntax

MySQL 8.1
SELECT column_list FROM table1
UNION
SELECT column_list FROM table2;

UNION ALL:

• Combines the results of two or more SELECT queries.
• Retains duplicates in the combined result.
• Performs faster as it doesn’t perform the additional operation of removing duplicates.

Syntax

MySQL 8.1
SELECT column_list FROM table1
UNION ALL
SELECT column_list FROM table2;