Question

Basically, I’m wondering if it’s possible to take this

IF @Value = 1
    SELECT col1, col2 FROM MyTable
ELSE
    SELECT col2 FROM MyTable

And do it in a single statement? Something like

SELECT IF(@Value = 1 col1), col2 FROM MyTable

I’ve tried this

SELECT case @Value when 1 then col1 end, col2 FROM MyTable

It always returns 2 columns, but the first will be null when @Value is not 1. I’d like it to return 2 columns only if @Value is 1, and one column the rest of the time.

Answer 1

With dynamic SQL, yes.

DECLARE @sql NVARCHAR(MAX);
SELECT @sql = N'SELECT ' + CASE WHEN @Value = 1 THEN
  'col1, ' ELSE '' END + 'col2 FROM dbo.MyTable;';
PRINT @sql;
--EXEC sp_executesql @sql;

Without dynamic SQL you can’t really change the shape of a resultset.