In MS Access, how do I update a table record to its current value plus the count of records in a different table? - sql

Question

I have two tables.
**tblMonthlyData**
ReportMonth | TotalItems | TotalVariances
Jan | 5 | 0
Feb | 1 | 1
Mar | 2 | 0
Apr | 8 | 4
May | 4 | 0
Jun | 5 | 0
Jul | 3 | 0
Aug | 5 | 0
Sep | 9 | 3
Oct | 1 | 0
Nov | 7 | 0
Dec | 6 | 0
and
**tblDailyData**
ID | ItemNum | CountedQty | SystemQty | Variance
1 | Item1 | 4 | 4 | 0
2 | Item2 | 8 | 5 | -3
3 | Item3 | 1 | 2 | 1
4 | Item4 | 6 | 4 | -2
For the sake of clarity, we'll say the above tblDailyData is from a count done today, 01/27/2017. Variance is a calculated field based on the data in both quantity fields.
I'm trying to add the count of records in tblDailyData to TotalItems in tblMonthlyData based on the date of the count (i.e. counts are done daily and each counts data needs to be added to the appropriate month in tblMonthlyData). So for the above example I'd need to add 4 (number of records) to TotalItems in tblMonthlyData for the Jan record, resulting in the updated record being 9, and add 3 (number of variances) to TotalVariances, resulting in the updated record being 3.
So far, I've tried using a Make Table Query for both total items counted and total number of variances, then using an Update Query that looks like this:
UPDATE tblMonthlyData
SET TotalItems = TotalItems + tblTempTotalItems.CountOfItems,
TotalVariances = TotalVariances + tblTempTotalVariances.CountOfVariances
WHERE Format$([ReportMonth],"mmm")=Format$(Now(),"mmm");
I've also tried a similar method using select queries to count records and variances (without creating the temporary tables) and running the update query based on those. Both methods result in Access prompting for the CountOfItems and CountOfVariances parameters when the update query is ran instead of just taking the values from the specified temporary table or select query.
This seemed like it'd be such a simple operation (query the count of records and variances, add them to the appropriate monthly record in separate table), but it turns out I can't figure out how to make it work. Thanks for any help!

Answer 1

This does not seem to be a situation for a table, but rather for some views/queries, which will always be up to date.
Use a GROUP BY FORMAT([date_field],"mm/dd/yyyy") clause in your query for daily item count (if you want to add that to a montlhy count, we will do that in ANOTHER query.
SELECT FORMAT([date_field],"mm/dd/yyyy") AS Date, COUNT(ID) AS TotalItems
FROM tblDailyData
GROUP BY Date
Call this query dailyTotalItems.
SELECT FORMAT([date_field],"mm/dd/yyyy") AS Date, COUNT(ID) AS TotalItemsWithVariance, SUM(
FROM tblDailyData
WHERE NOT (Variance = 0)
GROUP BY Date
Call this query dailyTotalItemsWithVariance.
SELECT MONTH([date_field]) As MonthDate, SUM(TotalItems) As TotalMonthlyItems
FROM dailyTotalItems
GROUP BY MonthDate
Call this query monthlyTotalItems.
SELECT MONTH([date_field]) As MonthDate, SUM(TotalItemsWithVariance) As TotalMonthlyItemsWithVariance
FROM dailyTotalItemsWithVariance
GROUP BY MonthDate
Call this query monthlyTotalItemsWithVariance.
Then LEFT JOIN both on MonthDate.
SELECT * FROM monthlyTotalItems
LEFT JOIN monthlyTotalItemsWithVariance ON monthlyTotalItems.MonthDate = monthlyTotalItemsWithVariance.MonthDate
NOTE: TotalItems will always be >= TotalItemsWithVariance AND every date with a variance must have had a count. So get ALL dates in monthlyTotalItems and left join to match the monthlyTotalItemsWithVariance items (which must be included, as shown above)