Question

I need to add around 600 columns to an existing table for testing purpose

declare @counter int
    set @counter = 1
    while @counter < 601
    begin

    ALTER TABLE Info ADD column+@counter varchar(max);
    set @counter = @counter + 1

    end

The column name should looks like column1,column2….column600

Answer 1

As this is purely for testing a quick and dirty way is to do this:

declare @counter int
set @counter = 1
declare @sql varchar(2000)

while @counter < 601
begin

Set @Sql = 'ALTER TABLE Info ADD column'+convert(varchar(10),@counter)+ ' varchar(max)'
Exec (@Sql)
set @counter = @counter + 1

end

Although I have to wonder why you would want 600 columns in a table