SQL 查询惟一数据/查询重复数据

 

//SQL 查询惟一数据/查询重复数据

--select  *  from MEMBER_FAVORITE where ROW_ID (not) in(
--select MAX(ROW_ID) from MEMBER_FAVORITE group by FAVORITE_TYPE,BLOCK_ID,MEMBER_ID
--)

 

1.FAVORITE_TYPE,BLOCK_ID,MEMBER_ID 惟一的标准。

2.无 not ,查询结果是 上述信息 显示惟一数据。

3.有 not ,  是预备删除的重复数据。

 

 

//   row number over 分页 

       condition = @" SELECT * FROM(
                                            select TOP " + (skip + count) + @"  
                                            *,
                                            ROW_NUMBER()
                                             OVER(" + sortSql + @") AS ROWID
                                            from BASE_BLOCK block 
                                            where  ... order by ...
                                            ) AS TEMP1
                                            WHERE ROWID>" + skip;

 

--ROW_NUMBER() 就是生成一个有顺序的行号,而他生成顺序的标准,就是后面紧跟的OVER(ORDER BY ID)
--还必须添加OVER语句以便告诉SQL Server你但愿怎样添加行序号，排序方式惟一，不然你会找不到你要的结果。