Question on HIVE CASE statement

[S, Iswarya]

Hi All,

I am trying to use a case statement in HQL script, but I get below error.

'Cannot recognize input near 'case'  'when'.

INSERT OVERWRITE TABLE tableA PARTITION (version= 107)
CASE WHEN $var == 'ABC' THEN
SELECT * FROM (
SELECT * FROM TableB
UNION ALL
SELECT * FROM TableC
UNION ALL
SELECT * FROM TableD
UNION ALL
SELECT * FROM TableE
UNION ALL
SELECT * FROM TableF
) MERGE;
ELSE
SELECT * FROM TableB
END

Any suggestions/ideas?

Regards,
Iswarya