Question

我的脚本是正确的，但完成的执行时间约为5分钟，删除了11320860条记录。是否有其他方式编写此查询以减少执行时间？

场景是相同的记录组合可以有E和A记录。如果同一组合中至少存在一条E记录，则代码会尝试删除A和E记录。

Delete from tableA u 
WHERE EXISTS
    (Select 1 from tableA w 
    WHERE w.a = u.a
    AND w.b = u.b
    AND w.c = u.c
    AND w.d = u.d
    AND w.flag ='E' ); - Del about 11320860 records in 4 Mins

Answer 1

所以你需要这个，我想：

Delete from tableA u 
WHERE u.flag in ('A', 'E')
  and EXISTS
    (Select 1 from tableA w 
      WHERE w.a = u.a
        AND w.b = u.b
        AND w.c = u.c
        AND w.d = u.d
        AND w.flag ='E')

这种方式也应该有效：

delete from tableA 
  where flag in ('A', 'E')
    and (a, b, c, d) in 
    (select a, b, c, d 
       from tableA 
      where flag = 'E')

使用一个条件

1 个答案: