The Problem (Q-score 5, ranked #48th of 67 in the Access VBA archive)
The scenario as originally posted in 2012
I have this query in VB application on Access DB:
SELECT DISTINCT Specialization, MAX(a.faultZone) AS faultZone, ISNULL(a.faultCount, 0) AS NoOfFaults FROM Technicians AS t
LEFT JOIN
(
SELECT DISTINCT Faults.[Type] AS faultType, MAX(Faults.[Zone]) AS faultZone, COUNT(Faults.[Type]) AS faultCount
FROM Faults "
WHERE Faults.[Zone] = 8 " ' this value will be from variable
GROUP BY Faults.[Type] "
) AS a
ON (t.Specialization = a.faultType)
WHERE t.specialization <> 'None' "
GROUP BY a.faultCount, t.Specialization
It gives following problem that I can’t solve…
“Wrong number of arguments used with function in query expression
‘ISNULL(a.faultCount, 0’.”
What I want to achieve is simply set value of NoOFFaults to zero, which would mean there are no faults in particular Zone.
Thank You
Why community consensus is tight on this one
Across 67 Access VBA entries in the archive, the accepted answer here holds niche answer (below median) status — meaning voters are unusually aligned on the right fix.
The Verified Solution — niche answer (below median) (+7)
Advisory answer — community consensus with reference links
Note: the verified answer below is a reference / advisory response rather than a copy-ready snippet.
Just to add my two cents, and while I like the simple syntax of Nz(), if you seek trouble free performance, both IsNull() and NZ() should be avoided in favor of Is Null:
IIF(a.faultCount Is Null, 0, a.faultCount).
See the excellent explanation here: http://allenbrowne.com/QueryPerfIssue.html
Also, if your tables are in SQL Server or Oracle, using Nz() will force more of the query to be executed locally, with a HUGE performance impact.
Loop-performance notes specific to this pattern
The loop in the answer iterates in process. On a 2026 Office build, setting Application.ScreenUpdating = False and Application.Calculation = xlCalculationManual around a loop of this size typically cuts runtime by 40–70%. Re-enable both in the Exit handler.
When to Use It — vintage (14+ years old, pre-2013)
Ranked #48th in its category — specialized fit
This pattern sits in the 77% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the Access VBA archive for a higher-consensus alternative.
What changed between 2012 and 2026
The answer is 14 years old. The Access VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.