如何查找同一列中的2个字段是否相等

Question

Table1
id     REQNo  Qty
D10   RD780  10
D1A   RD786  20
D20   RD34   30
D2A   RD34   40

有（1,2）（即）D1和D2的两个相等的子串

对于D1，如果RD780不等于RD786，那么数量将是相同的

对于D2，由于具有相同的RD34，因此sum（Qty）为70

必需的输出

id   ReqNo    Qty
D10   RD780  10
D1A   RD786  20
D20   RD34   70

Answer 1

create table #t(id varchar(10),reg varchar(10),qty int)
insert into #t values('D10','RD780',10),
('D1A','RD786',20),
('D20','RD34',30),
('D2A','RD34',40)

select min(id),reg,sum(qty) from #t group by reg

See Demo

Answer 2

这似乎有效：

declare @t table (id char(3),REQNo varchar(5),Qty int)
insert into @t(id,REQNo,Qty) values
('D10','RD780',10),
('D1A','RD786',20),
('D20','RD34', 30),
('D2A','RD34', 40)

select MIN(id) as id,REQNo,SUM(Qty) as Qty
from @t
group by SUBSTRING(REQNo,1,2),REQNo

对于最终只包含一行的组，MIN(id)与id相同，这是有用的。

id   REQNo Qty
---- ----- -----------
D20  RD34  70
D10  RD780 10
D1A  RD786 20

Answer 3

SELECT COUNT (*) , First_name, Last_Name, Mobile, Mobile1, Company, Job_title, Tel, Fax, Email, Email1, Country 
from dbo.Visitors 
where (your where statement) GROUP BY First_name, Last_Name, Mobile, Mobile1, Company, Job_title, Website, Tel, Fax, Email, Email1, Country 
HAVING COUNT (*)>1