Question

从文件编号栏中选择所有重复凭证编号，如果它在分配栏中有重复的条目，则选择该文件编号。

说：

Document No
111
123
121
111
111

Distribution
AAA
BBB
AAA
ABC
AAA

结果

111 AAA
111 AAA

Answer 1

首先使用group by和having clause

获取所有重复记录

select * from table where (Document_No,Distribution ) in (
select Document_No,Distribution  from table 
group by Document_No,Distribution having count(*) >1
)

或

select t1.Document_No,t1.Distribution from table t1 join 
(select Document_No,Distribution  from table 
group by Document_No,Distribution having count(*) >1
) as t2 on t1.Document_No=t2.Document_No and t1.Distribution=t2.Distribution

Answer 2

这是一个可能的解决方案：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
     // fetch data in background thread 
});

Answer 3

SELECT
    [Document No],
    Distribution
FROM Document
GROUP BY [Document No], Distribution
HAVING COUNT(*) > 1

如何在MS Access Query中翻译此语句？

3 个答案: