Average

[Bill]

I have a table organized by weather station and date but i need to average
across days. below is an example of my data.
STATION DATE TEMP AVG
station1 1/1/2005 20
station1 1/2/2005 24 22
station1 1/3/2005 26 25
station2 1/1/2005 20
station2 1/2/2005 24 22
station2 1/3/2005 26 25

 

[Allen Browne]

Use a subquery to calculate the average for the station + date.

If subqueries are new, here's an example:
http://allenbrowne.com/subquery-01.html

If that approach seems too difficult, you could create a Totals query that
gives you the average for the day. Then join that to your original table in
another query.

 

[Bill]

I let that method run all night and the query never completely finished. Is
there a faster method?

 

[Allen Browne]

Did you try the Totals query?

 

[Bill]

i dont know how to do that.

Did you try the Totals query?

 

[Allen Browne]

1. Create a query.

2. Depress the Total button on the toolbar.
Access adds a Total row to the design grid.

3. In the total row beneath the Station and date fields, accept Group By.

4. In the Total row beneath the temperature field, choose Average.

 

[Bill]

but that would just average by day, the average happens across days. for
example 1/1 is averaged with 1/2 and 1/2 is averaged with 1/3 and so on.

 

[Allen Browne]

Okay: I have not understood your example.

If an average is calculated across days, you will need to take the time to
learn the subquery approach.