This post is a testimonial, NOT a question!
I get an error when I perform a TOTALS query on a successful SELECT query.

The error message starts with "This expression is typed incorrectly, or it is too complex to be evaluated". The error is thrown when I enter a parameter.
The error is a common error thrown by Access when someone tries to pack too many clever phrases into one SQL.


In my case, I have generated a record set with nested SELECT queries. In other words, one query is based upon another query. This is not a "subquery" in the literal sense. I use the results of one query, rstA, to provide the record set, rstB, for the second query. rstB takes a parameter.
Then a third query, rstC, takes rstB and performs a GROUP BY function to sum groups of records in rstB.
The error is thrown if there is a null in one of rstB's fields that will be summed by rstC.
I am posting this message NOT for input, but, instead, as a small testimony to the community. The error was subtle because the queries were simple, only the aggregation was failing, and the error message is quite generic. Perhaps someone else with a similar problem will run across this post.
By thinking carefully about how to articulate the problem to post a question on this forum, I thought of a test that exposed the issue. I had tried many changes to the queries to no avail. Then I thought about replacing the parameter with a constant! This is a very obvious technique for debugging programs, but only after great frustration! Access produced a very different error message that pointed me directly to the problem. When I ran the TOTALS query (rstC) with the constant, rather than the parameter, in rstB, this error was thrown: "Invalid use of NULL".
Perhaps a good lesson for us all!