SQL Server - Differences between Union and UnionAll

The below are the differences between Union and Union ALL .

S.No	Union	UnionAll
1	This is used to eliminate duplicate rows	It will not eliminate duplicate rows
2	t can be used to combine any number of queries	It can be used to combine maximum of 2 queries
3	It cannot contain aggregate functions	It can contain aggregate functions
4	Union is slower than UnionAll	UnionAll is faster than Union
5	Output is in sorted order Example : SELECT Col FROM @Table1 UNION SELECT Col FROM @Table2 Result: 1 2 3 5	Output is not in sorted order Example : SELECT Col FROM @Table1 UNION ALL SELECT Col FROM @Table2 Result: 1 2 3 2 5