sql - 从多个相关表中删除行

Question

标识符上有三张表，一一对应。我需要从符合条件 A.ID = B.ID = C.ID 的三个表中删除所有记录

现在我按照以下方式进行:

DECLARE
    CURSOR CUR IS 
        SELECT C.ID FROM A 
        INNER JOIN B ON A."ID" = B."ID" 
        INNER JOIN C ON B."ID" = C."ID"
        WHERE A.STATUS = 'ERROR';
    IDX NUMBER;
BEGIN
    FOR REC IN CUR LOOP 
        IDX := REC.ID;
        DELETE FROM C WHERE C."ID" = IDX;
        DELETE FROM B WHERE B."ID" = IDX;
        DELETE FROM A WHERE BP."ID" = IDX;
    END LOOP;
    COMMIT;
END;

大量数据，这种方式可以进行很长时间的运行。有什么办法可以更快的删除吗？

Answer 1

您可以创建一个 PL/SQL 类型来存储 ID。

CREATE TYPE t_ids AS TABLE OF NUMBER;

从表中删除所有记录 a匹配条件，并将 ID 返回到该类型的变量中。然后从 b 中删除所有记录和 c有了这些 ID。

DECLARE
  ids_to_delete   t_ids;
BEGIN
  DELETE FROM a
   WHERE a.status = 'ERROR'
     AND EXISTS ( SELECT 1 FROM b WHERE b.id = a.id )
     AND EXISTS ( SELECT 1 FROM c WHERE c.id = a.id )
  RETURNING a.id
  BULK COLLECT INTO ids_to_delete;

  DELETE FROM b
   WHERE id IN ( SELECT COLUMN_VALUE FROM TABLE( ids_to_delete ) );

  DELETE FROM c
   WHERE id IN ( SELECT COLUMN_VALUE FROM TABLE( ids_to_delete ) );
END;

这应该表现得更好，因为它不需要循环并且在三个 SQL 语句中完成所有事情，而不是每个 ID 三个语句。