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sql 查询时如何去掉重复的部分写在whErE中

你说的重复是指两条记录完成一样么,如果是则用 SELECT DISTINCT COLUMN1,COLUMN2 FROM TABLE1 或 SELECT COLUMN1,COLUMN2 FROM TABLE1 GROUP BY COLUMN1,COLUMN2 若你要查询出来的字段在两条记录中有不同值,可以用MAX() 或者可以根据你自己...

那就建一个视图,只存放这几个固定ID,然后用的时候直接用该视图查询好了。 create view 视图名(自己起名字)asselect* from 表名where ID in ('','',''.....)go

select col1,col2,col3 from (select col1,col2,col3, row_number() over(partition by col1 order by col2 desc) rn from table_name ) a where rn=1

条件写成where _identify (between 1 and 29) and (between 31 and 32)是错误的,这样的条件得不到任何符合条件的记录。 要剔除部分记录,可以用条件不等于或者not in,例如: where _identify between 1 and 32 and not in (30)

SELECT * FROM 表名 WHERE ROWID IN ( SELECT MIN(ROWID) FROM 表名 GROUP BY 列1, 列2, 列3 ) 如果不是Oracle数据库,可以将ROWID替换为主键来进行。

sql中在where字句里截取字符方法如下: 1、如果是sqlserver:where left(p.end_time,4) = '2012'。 2、如果是Oracle:where substr(p.end_time,0,4) = '2012'。 举例: 1、oracle: 'where substr(字段名,1,2)='''123'''' 2、sqlserver: 'where s...

1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) 2、删除表中多余的重复记录,重复记录是根据单个...

select * from a where b in(‘1’ , ‘2’, ‘3’) and c '4'

比如在Northwind数据库中有一个查询为 SELECT c.CustomerId,CompanyName FROM Customers cWHERE EXISTS(SELECT OrderID FROM Orders o WHERE o.CustomerID=c.CustomerID) 这里面的EXISTS是如何运作呢?子查询返回的是OrderId字段,可是外面的查...

select id, name, memo from A where id in (select id from A group by id having count(1) >= 2) select id, name, memo from A where id in (select id from A group by id having count(1) >= 2)

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