UNION 연산자

UNION - 두개 이상의 테이블 또는 쿼리를 합치는 역할 - UNION ALL은 중복을 포함한 모든 값을 나타내는 것 ex) SELECT 'min' AS TYPE, MAX(ymdhm) AS END_DATE, MIN(ymdhm) AS START_DATE FROM ti_hrf_bo_mi A UNION SELECT 'dy' AS TYPE, MAX(ymdhm) AS END_DATE, MIN(ymdhm) AS START_DATE FROM ti_hrf_bo_dy UNION SELECT 'hr' AS TYPE, MAX(ymdhm) AS END_DATE, MIN(ymdhm) AS START_DATE FROM ti_hrf_bo_hr; 실행화면...