Get difference of Min and Max

[nazimscr]

Dear All,



I am part of a fleet management company with many trucks and I am trying to develop a database which will tell us the life of each tires in terms of kilo meters. Query should be able to tell us how much km has the tire being driven in different trucks. Below are the different scenarios of changing tires.

1. New tires installed in the truck. Vehicle KM is recorded (in the current km field in the attached file), this value can be recorded as Min value.
2. Tires are transfered within trucks, again vehicle Km is recorded.
3. Tires are trasnfered between trucks with vehicle closing KM recorded in current km field, this value would the Max value.

By taking the difference of Max and Min Km, i will be able to generate how much km each tires has produced, however due to scenario 3 (transferred between trucks) this logic will not work. Therefore i thought of using a calculated field which will be concatenation of truck number and tire number ie field T&T combined.

I would like to create a query which tell me how km each tires has produced.

My apologies i am new to access with little knowledge of query.

I have attached the file, my data is in the tasks table. i think calculation should be based on only 3 fields 1) truck number 2) current KM and 3) Tyre number

I would really appreciate your help on this regard.

Regards,

Nazim

[June7]

You want to calculate values from related records. This will probably require subquery. Review http://allenbrowne.com/subquery-01.html