问题：设表T中有五个字段A，B，C，D，ID，其中ID字段是为自动增量整型字段(唯一值)。业务数据生成时有重复插入现象，现需对A、B、C、D四字段完全一样的脏数据进行清理，要求设计一SQL语句，对四个字段完全一样的记录，仅保留ID最小的一条，其余作删除处理。
DELETE FROM T WHERE [ID] IN
(
select [ID] from T where A in
(select A from T Group By A,B,C,D Having count(*)>1)
and [ID]<>
(select min(ID) as minID from T Group By A,B,C,D Having count(*)>1)
)
更正：
delete from T
where T.ID not in (select min(ID) from T group by T.A,T.B,T.C,T.D)
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