2-2-4. actual time 해석

-- [SQL-2-2-4-a]

EXPLAIN (ANALYZE,COSTS OFF)
SELECT  TO_CHAR(t1.ord_dtm,'YYYY') ord_yy ,SUM(t1.ord_amt) ord_amt_sum
FROM    startdbpg.tr_ord t1
WHERE   t1.ord_dtm >= '2019-01-01'::date
AND     t1.ord_dtm <  '2021-01-01'::date
GROUP BY TO_CHAR(t1.ord_dtm,'YYYY')
ORDER BY ord_yy DESC;
SQL
복사

-- [SQL-2-2-4-b]

EXPLAIN (ANALYZE,COSTS OFF)
SELECT  /*+ HashJoin(t1 t2) */
        t1.*, t2.*
FROM    startdbpg.tr_ord t1
        INNER JOIN startdbpg.ms_mbr t2
            ON (t2.mbr_id = t1.mbr_id)
WHERE   t1.ord_dtm >= '2019-01-01'::date
AND     t1.ord_dtm <  '2021-01-01'::date;
SQL
복사

-- [SQL-2-2-4-c]

EXPLAIN (ANALYZE,COSTS OFF)
SELECT  /*+ NestLoop(t1 t2) NoMemoize(t1 t2) */
        t1.*, t2.*
FROM    startdbpg.tr_ord t1
        INNER JOIN startdbpg.ms_mbr t2
            ON (t2.mbr_id = t1.mbr_id)
WHERE   t1.ord_dtm >= '2019-01-01'::date
AND     t1.ord_dtm <  '2021-01-01'::date;
SQL
복사