Question

而不是更新我的DBA要求我删除然后将值插回到表中以获得性能。我需要在这里使用merge。我之前没有合作过。我该如何继续这样做？下面给出的是删除和插入查询。可以合并用于删除和单独插入而不进行任何更新吗？

 DELETE FROM hist_tab1 hist
     WHERE hist.tranid IN (SELECT t.tranid
                                    FROM transaction_tab t
                                   WHERE t.tran_status =
                                            'Posted');

 INSERT INTO hist_tab1 (tranid,
    tranamt,
    date,
    post_date,
    isvalid,
    salescode)
   (SELECT tnr.tranid,
           tranamt,
           date,
           post_date,
           isvalid,
          salescode
    FROM tab1 tnr,
          (SELECT tranid
           FROM transaction_tab t
           WHERE t.tran_statu IN ('Posted','Verified')) tt
    WHERE tnr.tranid = tt.transid);

Answer 1

删除适用于更新。但它只会删除目标表更改的行并满足where子句。否则你可以使用一些虚拟列并尝试更新并将删除子句放在下面。

e.g。

Merge into hist_tab1 src using 
((SELECT tnr.tranid,
           tranamt,
           date,
           post_date,
           isvalid,
          salescode
    FROM tab1 tnr,
          (SELECT tranid
           FROM transaction_tab t
           WHERE t.tran_statu IN ('Posted','Verified')) tt
on tnr.tranid = src.transid
when matched then update src.dummy = tt.dummy
delete where tt.tranid IN (SELECT t.tranid
                                    FROM transaction_tab t
                                   WHERE t.tran_status =
                                            'Posted')
when not matched INSERT (src.tranid,
    src.tranamt,
    src.date,
    src.post_date,
    src.isvalid)
values
(trg.tranid,
    trg.tranamt,
    trg.date,
    trg.post_date,
    trg.isvalid
)

） salescode）

使用MERGE进行删除并在oracle中插入

1 个答案: