Evaluation of a Query

[Guest]

Update Query has two columns Column A and Column B.
Column B is a calculation based on the value of Column A.
If columns are 'evaluated' left to right shouldn't I be able to do this in
in one query rather than two.

 

[Douglas J Steele]

Realistically, you shouldn't be storing calculated values.

As fellow Access MVP John Vinson likes to say "Storing calculated data
generally accomplishes only three things: it wastes disk space, it wastes
time (a disk fetch is much slower than almost any reasonable calculation),
and it risks data validity, since once it's stored in a table either the
Total or one of the fields that goes into the total may be changed, making
the value WRONG."

Rather than storing the calculation, create a query that has a calculated
field in it, and use the query wherever you would otherwise have used the
table.

 

[Guest]

Thank you for your assistance Douglas.

Realistically, you shouldn't be storing calculated values.

As fellow Access MVP John Vinson likes to say "Storing calculated data
generally accomplishes only three things: it wastes disk space, it wastes
time (a disk fetch is much slower than almost any reasonable calculation),
and it risks data validity, since once it's stored in a table either the
Total or one of the fields that goes into the total may be changed, making
the value WRONG."

Rather than storing the calculation, create a query that has a calculated
field in it, and use the query wherever you would otherwise have used the
table.