HIVE UNION

UNION

The UNION operator in HIVE is used to combine the contents the two or more SELECT statements.

Syntax:

SELECT column1,column2,...columnN FROM table1
UNION
SELECT column1,column2,...columnN FROM table2;

Note : There should be equal number of columns in both SELECT statement.

UNION ALL

The only new thing about UNION ALL is that it retains the duplicates from both tables.

Syntax:

SELECT column1,column2,...columnN FROM table1
UNION ALL
SELECT column1,column2,...columnN FROM table2;