union all的坑， FAILED: ParseException cannot recognize input near ‘(‘ ‘SELECT‘ ‘‘ in select clause

union all后面需要是用select查出的子表，不能是直接写一个子表名在那！！！

SELECT
c1,
c2
from t1 where ...... 

union all 

SELECT
c1,
c2
from t2 where ...... 
-- 正确



SELECT
c1,
c2
from t1 where ...... 

union all 

(
SELECT
c1,
c2
from t2 where ...... 
) p

-- FAILED: ParseException line 8:0 cannot recognize input near '(' 'SELECT' 'c1' in select clause



SELECT
c1,
c2
from t1 where ...... 

union all 

SELECT
*
from
(
SELECT
c1,
c2
from t2 where ...... 
) p
-- 正确

以上是在hive下，mysql下大可能也是这样！！