전부 선택
select rdate, tot, g1, g1, g3, g4, g5, g6, g7, g8 dtype from `cc_3f_test`
NULL 이 아닌것 선택
select rdate, tot, g1, g1, g3, g4, g5, g6, g7, g8 dtype from `cc_3f_test` where tot is not null
NULL 인것 선택
select rdate, tot, g1, g1, g3, g4, g5, g6, g7, g8 dtype from `cc_3f_test` where tot is null
