[SQL] exists 함수

-- 쿼리
select
    SUBSTR(T.TABLENAME,1,2)
    ,   case SUBSTR(T.tablename,1,2)
             when 'CC' THEN '코드정보'
             when 'MR' THEN '의무기록'
             when 'PE' THEN '처방 및 결과'
             when 'PT' THEN '환자'
             when 'RG' THEN '내원'
             when 'TA' THEN '비정형'
             else null
        end                                 as SUBSTRDESC
    , T.TABLENAME
    , T.DESCRIPTION
    , C.ATTNAME
    , C.DESCRIPTION
from
    CRDW.._v_table T INNER JOIN crdw.._v_relation_column C
        on
            T.tablename = C.name and
            T.objtype like 'TABLE'
where exists(
			 select *
			 from(select   '[컬럼명]' 			as ATTNAME
						 , '[테이블명]' 	   as TABLENAME
				  from crdw..[테이블명]
				  where crdw..regexp_like([컬럼명],'[검색어]','I')
				  limit 1
				  ) D
		where ATTNAME = C.ATTNAME
		  and TABLENAME = T.TABLENAME 
		  	)
;

어떤 (착한)선생님이 날 시험했다.

정리는 이따가 할랭