Select single value from database(when table have multiple similar values) in c#

Question

I have a table with 3 columns PrjId, prjname and station. Here is my table example:

PrjId     prjname     station
1         test1       s1
1         test1       s2      
1         test1       s3

I want to fetch projects from project_detail table into a dropdown. Here is my SQL query

select * from project_detail where prjname <> '' and PrjId is not null;

The issue is instead of one test1 project all 3 test1 are displayed in dropdown. I know I have to put some condition but I am not understanding how to do it. Pease help.

Possible duplicate of [How to select unique records by SQL](https://stackoverflow.com/questions/1641718/how-to-select-unique-records-by-sql) — unicorn2, Jun 20 '17 at 08:13

score 3 · Accepted Answer · edited Jun 20 '17 at 06:23

3

select Distinct prjname 
 from project_detail where prjname <> '' and PrjId is not null;

edited Jun 20 '17 at 06:23

Romano Zumbé

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answered Jun 20 '17 at 06:20

Ankesh Kumar

515
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Steve · Answer 2 · 2017-06-20T06:35:52.947

You requirements are for the DISTINCT keyword

select DISTINCT prjname 
from project_detail 
where prjname <> '' and PrjId is not null;

This will give you a list of the unique prjname in your table.

However there is something that seems not quite right in that table.

If you want to describe a relationship between projects and stations where a project is present in many stations and a station could have many projects then a more correct approach could be with three ralated tables, one for the projects and one for the stations and one for the relationship between the projects and the stations

Project_Detail
---------------
idproj
prjname
....other specific project attributes

Station_Detail
----------------
idstation
stname
....oter specific station attributes

Project_Station
----------------
idprj
idstation
....other specific relationship attributes
....like for example dateofinstall,active etc...

score 0 · Answer 3 · answered Jun 20 '17 at 06:21

0

select Distinct PrjId, prjname  from project_detail where prjname <> '' and PrjId is not null;

It can work for you.

answered Jun 20 '17 at 06:21

Tien Nguyen Ngoc

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1
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Select single value from database(when table have multiple similar values) in c#

3 Answers3