I am working on MS-Access where i have a simple table with 3 columns : sub1,sub2 & total.My doubt is:?

Question

i just want to add the sub1 and sub2 columns for which i set the validation rule of total to: [sub1]+[sub2]

but then i get the error: "Cannot use multiple columns in a column level check constraint"
what does that mean and how to get around it?

Answer 1

Create table with 2 columns (sub1 and sub2)
and create a Query to display both along with calculated total (that the easiest way, but there are others).

Validation rule is used to validate entered value, not calculate it.

Answer 2

you could probably do the same with only two columns (sub1 and sub2) and when you need the total just select sum(sub1,sub2).