C# sql server conversion failed error nvarchar value to int?

Question

How to fix this issue in my code:

str = "SELECT " + columnName + " FROM [tableA] where Company_ID=" + HaksId.ToString() + "";
cmd.CommandText = str;
cmd.Connection = conn;
adpt.SelectCommand = cmd;
adpt.Fill(ds);

In the above code there is only required things mentioned obviously conn is connection string I have mentioned all things they are working fine there is some other error in this code

Where columnname is string and Id is integer

Error is

Conversion failed when converting the nvarchar value '[Select]' to data type int.

Return value is value of type decimal(18,0)

Hoping for your suggestion

Thanks

EDITED

columname="Avg"
HaksId=1

Company_ID is of nvarchar

Result of query should be 2.

SOLUTION

This help me out,

"SELECT " + columnName + " FROM [tableA] where Company_ID='" + HaksId+ "'"

We can't see the values of columnName or HaksId; so: what is the resulting value of str here? Also: Does ds.Tables[0] have columns defined? If so: as what? — Marc Gravell
– Marc Gravell, Commented Aug 20, 2014 at 9:51
Company_ID = int isn't it? if it's, then u're comparing it with string. — NomNomNom
– NomNomNom, Commented Aug 20, 2014 at 9:55
I would suggest using a parameter for the ID. It might also help with the confusion of types. — Amber
– Amber, Commented Aug 20, 2014 at 9:57

Trent · Accepted Answer · 2014-08-21 05:07:01Z

2

Parameters should solve the problem here. I would change this;

str = "SELECT " + columnName + " FROM [tableA] where Company_ID=" + HaksId.ToString() + "";

To this;

str = "SELECT " + columnName + " FROM [tableA] where Company_ID = @CompanyID";

Then use this;

adpt.SelectCommand.Parameters.Add("@CompanyID", SqlDbType.Int).Value = Haks;
adpt.Fill(ds);

edited Aug 21, 2014 at 5:07

answered Aug 20, 2014 at 10:07

Trent

1,59315 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

user3664724 Over a year ago

columnID does not exsis in the current context

marc_s Over a year ago

See Can we stop using AddWithValue already? - I would recommend to use a "normal" Parameters.Add(....).Value = .... approach.

marc_s Over a year ago

@FizzBuzz: read the article I linked to! It explains in great detail why AddWithValue is dangerous

Trent Over a year ago

@marc_s Err, didn't realise it was a link, my bad. Nice article and duly noted.

Collectives™ on Stack Overflow

C# sql server conversion failed error nvarchar value to int?

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related