oracle中刪除重復記錄-文庫吧
2025-04-28 22:33 本頁面
【正文】 3 che 2 3 che 3 4 dff 3 4 dff 3 4 dff 4 5 err 5 3 dar 6 1 wee 7 2 zxc20 rows selected.：(1).sqlselect * from cz group by c1,c10,c20 having count(*) 1。 c1 c10 c20 1 2 dsf 2 3 che 3 4 dff(2).sqlselect distinct * from cz。 c1 c10 c20 1 2 dsf 2 3 che 3 4 dff(3).sqlselect * from cz a where rowid=(select max(rowid) from cz where c1= and c10= and c20=)。 c1 c10 c20 1 2 dsf 2 3 che 3 4 dff：(1).適用于有大量重復記錄的情況(在c1,c10和c20列上建有索引的時候，用以下語句效率會非常高)：sqldelete cz where (c1,c10,c20) in (select c1,c10,c20 from cz group by c1,c10,c20 having count(*)1) and rowid not in(select min(rowid) from cz group by c1,c10,c20 having count(*)1)。
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