怎樣查詢數(shù)據(jù)庫中重復的數(shù)據(jù)？1、查找表中多余的重復記錄，重復記錄是根據(jù)單個字段（peopleId）來判斷select * from peoplewhere peopleId in (select

怎樣查詢數(shù)據(jù)庫中重復的數(shù)據(jù)？

1、查找表中多余的重復記錄，重復記錄是根據(jù)單個字段（peopleId）來判斷

select * from peoplewhere peopleId in (select peopleId from people group by peopleId having count (peopleId) > 1)

2、刪除表中多余的重復記錄，重復記錄是根據(jù)單個字段（peopleId）來判斷，只留有rowid最小的記錄

delete from people where peopleId in (select peopleId from people group by peopleId having count (peopleId) > 1)and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

3、查找表中多余的重復記錄（多個字段）

select * from vitae awhere (a.peopleId，a.seq) in (select peopleId，seq from vitae group by peopleId，seq having

如何查找數(shù)據(jù)庫中的重復數(shù)據(jù)？

下面以 sqlserver數(shù)據(jù)庫為例進行說明。 select * from TableA where b in (select b from TableA group by b having count(b) > 1) 這樣就列舉出了b字段所有的重復數(shù)據(jù)，可以根據(jù)對應的行號，取得位于第幾行。 如果要查詢a字段或者c字段重復數(shù)據(jù)，可以相應的把上面的b字段替換成a字段或c字段即可。 舉例： 1、創(chuàng)建表student 2、查詢語句: select * from student where name in (select name from student group by name having count(name ) > 1) 這樣就查出名字重復列，以及行號id。

SQL數(shù)據(jù)庫多表連接查詢?yōu)槭裁磾?shù)據(jù)會重復？

1、用select語句，查看兩個表中的數(shù)據(jù)，確認下來的結(jié)果是每個表中都只有兩行數(shù)據(jù)；

2、嘗試著用最常用的兩表結(jié)合查詢方式來看看結(jié)果----結(jié)果重復出現(xiàn)，并且結(jié)果錯誤：select a.pono，a.p_name，a.p_kg as 系統(tǒng)重量，b.p_kg as 實際重量 from test1 a，test2 b where a.pono=b.sono；

3、執(zhí)行完整代碼，可以得出結(jié)果，select isnull(a.pono，b.sono) as pono，isnull(a.p_name，b.p_name) as p_name， a.p_kg as 系統(tǒng)重量、 b.p_kg as 實際重量、 from test1 as a 、full join test2 as b on a.pono = b.sono、and a.p_name = b.p_name。