What is Union and Union All operator?

- Union is used to combine distinct records from two tables.

- Union all combines all records from two tables.

What is Union and Union All operator?

- UNION is a set operator combines the relations of 2 or more select statements into one relation. Each select statement of UNION operator must have same number of columns with similar data types. Also the columns in both the select statements must in the same order. UNION selects only distinct values.

- UNION ALL is a set operator performs the same functionality that of UNION, with one exception – allowing duplicates values in the relations.