SQL query no results

[mbedford]

How can I make a query return zero values when there are no results?

The first level of queries returns data from tables based on a selection made in a form and reported in a different query.

The base query, qryPrintCostAssets, returns all data from tblAssets based on a selection in a form. qryPrintCostAssets.ID is key to the rest of the queries pulling their data.

SELECT *
FROM tblAssets
WHERE (((tblAssets.ID)=Forms!formPrintCost!listPrinter));
 

qryPrintCostSupport pulls from tblSupport based on qryPrintCostAssets.ID. When there are no entries in tblSupport for a particular printer, qryPrintCostSupport returns a row of empty cells.

SELECT qryPrintCostAssets.ID AS AssetID, Left([tblSupport.Problem],50) AS Problem, tblSupport.Date, tblSupport.DownTime, tblSupport.Cost
FROM tblSupport INNER JOIN qryPrintCostAssets ON tblSupport.AssetID=qryPrintCostAssets.ID
ORDER BY tblSupport.ID;
 

qryPrintCostMeter does the same as qryPrintCostSupport, except it is pulling from tblPrinterMeter for meter readings (page counts). The syntax is essentially the same except the fields are numeric except for the AssetsID field, which is exactly the same as in qryPrintCostSupport. No entries in tblPrinterMeter results in a row of empty cells.

Then there are 2 queries dependent on these two queries. qryPrintCostSupportCostTotals sums qryPrintCostSupport.Cost:

SELECT qryPrintCostAssets.ID AS AssetID, Sum(qryPrintCostSupport.Cost) AS SCost
FROM qryPrintCostAssets INNER JOIN qryPrintCostSupport ON qryPrintCostAssets.ID=qryPrintCostsupport.AssetID
GROUP BY qryPrintCostAssets.ID;
 

If the results of qryPrintCostSupport are a row of empty cells, the result of qryPrintCostSupportCostTotals is no cells under the column titles.

The same holds true for qryPrintCostMeterTotals, which uses the MAX value from the qryPrintCostMeter fields to find the highest value for BCount (black), CCount (color), and TCount (total). If qryPrintCostMeter is a row of empty cells, qryPrintCostMeterTotals returns no cells under the column headers.

When either qryPrintCostMeterTotals or qryPrintCostSupportCostTotals has no cells, qryPrintCostMaster also returns no cells under the column headers/titles.

qryPrintCostMaster uses multiple INNER JOINs to pull data from several other queries all tracing back to qryPrintCostAssets in one way or another for the purpose of populating fields in a form to track printer costs.

SELECT qryPrintCostAssets.ID AS AssetID, qryPrintCostAssets.UID, qryPrintCostAssets.ModelID, qryPrintCostAssets.Status, qryPrintCostAssets.Dept, qryPrintCostAssets.SubDept, qryPrintCostAssets.SN, qryPrintCostAssets.Box, qryPrintCostAssets.BoxDrop, qryPrintCostAssets.NetName, qryPrintCostAssets.MACAddress, qryPrintCostAssets.IPAddress, qryPrintCostAssets.Description, qryPrintCostAcquire.ID AS AcquireID, qryPrintCostAcquire.Method, qryPrintCostAcquire.Price, qryPrintCostAcquire.DateAcquired, qryPrintCostAcquire.Number, qryPrintCostAcquire.LeaseBegin, qryPrintCostAcquire.LeaseEnd, qryPrintCostAcquire.Vendor, qryPrintCostMeterTotals.BCount, qryPrintCostMeterTotals.CCount, qryPrintCostMeterTotals.TCount, qryPrintCostSupportCostTotals.SCost
FROM ((qryPrintCostAssets INNER JOIN qryPrintCostAcquire ON qryPrintCostAssets.ID=qryPrintCostAcquire.AssetID) INNER JOIN qryPrintCostSupportCostTotals ON qryPrintCostAssets.ID=qryPrintCostSupportCostTotals.AssetID) INNER JOIN qryPrintCostMeterTotals ON qryPrintCostAssets.ID=qryPrintCostMeterTotals.AssetID;
 

What is the difference between a query returning empty/blank cells and a query returning no cells?

Is there error correction or handling that I can employ in SQL that would ultimately allow qryPrintCostMaster to return the expected row of values simply excluding those for which there are none?

[Oralloy]

You might want to try using an outer join, rather than an inner join.

Just because you see a blank row in the output display doesn't mean that there is actually anything there.

[mbedford]

Is the syntax the same for INNER and OUTER joins?

What are the substantive differences between the two?

What are examples of times one and the other are appropriate?

[mbedford]

Ok, figured this out with the pointers you gave, Oralloy. Thank you.

I want to be able to do more things with the two queries qryPrintCostSupport and qryPrintCostMeter, so the fix had to work by that point in the query ladder.

So I changed the INNER JOINs in those two queries to RIGHT JOINs (which Access trimmed down from RIGHT OUTER JOINs that I'd typed). When there is no data in either tblSupport or tblPrinterMeter for a selected printer, they return a single record with only the AssetID populated.

This gets handed down to qryPrintCostMeterTotals and qryPrintCostSupportCostTotals which, because it's an actual record and not a blank return, show the same record with only the AssetID populated. And the qryPrintCostMaster shows all available information for the selected printer as a single record without erroring when data is not available in one or both of those fields.

Thank you for the help.

[Oralloy]

Glad to help.

Good luck with your project.

Oralloy