select with parameter instead of field name

Question

How can I use a parameter instead of a field name like:

Declare @Thecode varchar(10)
Set @Thecode= ‘code’   --'code' is field name. 
Select @Thecode from sqltable

Answer 1

Here is the correction in your query:

SET @Thecode= ‘code’   --'code' is field name. 
SET @query='Select '+@Thecode+' from sqltable'
EXECUTE(@query)

There are two ways to execute dynamic SQL in SQL Server: use the sp_executesql system stored procedure or the EXECUTE() operator. And for more details about the dynamic SQL execution Follow the below link:

https://www.mssqltips.com/sqlservertip/1160/execute-dynamic-sql-commands-in-sql-server/

Answer 2

I think you are looking for the Dynamic SQL.

If it is so then please check the following solution:

Note: Tested in SQL Server 2008 R2

Declare @Thecode varchar(10)
DECLARE @query VARCHAR(MAX)

Set @Thecode= 'code'   --'code' is field name. 

SET @query = 'SELECT '+ @Thecode +' from sqltable';

EXEC(@query)

Always mention the DBMS in the tags while posting the question. And take care of SQL Injection

For more details about Dynamic SQL.