問題：設表T中有五個字段A，B，C，D，ID，其中ID字段是為自動增量整型字段(唯一值)。業務數據生成時有重復插入現象，現需對A、B、C、D四字段完全一樣的臟數據進行清理，要求設計一SQL語句，對四個字段完全一樣的記錄，僅保留ID最小的一條，其余作刪除處理。 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)
