SQL Calculated field selected values

Question

I have a SQL View with columns IDX, DATE, SIGNAL, VALUE We have SIGNAL1 to SIGNAL10 What I want is that on Daily basis a computed column which is calculated as follows:

Compval= SIGNAL7*SIGNAL8-SIGNAL9

Other columns retain the original values

How to do this?

Answer 1

You can create another view or just add this column to your view:

create view v_view as
    select v.*, (SIGNAL7*SIGNAL8-SIGNAL9) as CompVal
    from first_view v;

Answer 2

在MS SQL Server中，您可以添加如下所示的计算列

    ALTER table TableA ADD compVal AS SIGNAL7*SIGNAL8-SIGNAL9