"Formula" In a Database

[carl]

My database records look column a,b,c:

Date Time Code Difference
20060428 93155 53
20060428 93155 85 32
20060428 93157 86 1
20060429 93159 54 -32
20060429 93159 55 1
20060429 93205 87 32
20060429 93205 88 1

I am trying to create the field "Difference" which is the subtraction of the
preceeding record for field "Code".

Is this possible in Access ?

 

[freakazeud]

Hi,
as a general rule we do NOT want to store calculated values in tables.
HTH
Good luck

 

[carl]

Thank you. I do not need to store the value. I need it to filter on.

I am trying to pull out all records where the "Difference" is not equal to 1.

Is this possible in Access ?

 

[gee664]

if your table has an incremental autonumber id field, you could create
views based on the (id - 1) and and then join the 2 views in another
view to calculate the difference and spit out the records you want..

or

you can use vba.

 

[Steve Schapel]

Carl,

It is possible to compare the value of a field with the value in the
same field in the "previous" record - so long as there is a data-based
way to determine which is the previous record. In the sample data you
gave, this does not appear to be the case, as there are duplicate data
on both the Date and Time fields.

 

[Van T. Dinh]

See a similar SQL String in:

http://www.tinyurl.com/zhhsz