Code:
SELECT Productivity.Product, Productivity.LotNumber, Productivity.YardsOn, Productivity.YardsOff, (FormatPercent([YardsOff]/[YardsOn])), (((DateDiff("n", [StartTime], [EndTime])) / 60) - ([SetUpTime]+[CleanUpTime]+[MaintUnschedDT]+[TestUnschedDT]+[OtherUnschedDT]+[MixUnschedDT]+[RTODT])), ([YardsOff]/(((DateDiff("n", [StartTime], [EndTime])) / 60) - ([SetUpTime]+[CleanUpTime]+[MaintUnschedDT]+[TestUnschedDT]+[OtherUnschedDT]+[MixUnschedDT]+[RTODT]))), Note FROM Productivity WHERE (((Productivity.ProdDate)=Forms!Form1!CategoryID))
UNION SELECT DISTINCT Null, null, null, null, null, null, null, null FROM Productivity ORDER BY Productivity.Product;
This is the query running your second combo box (which I assume needs to have something in it to populate the rest of the form) but it when I click the down arrow on the combo box I get an error. What is this doing on your form (look at the sample database you constructed not your original database). Are you calling a function that you've written with this code? The error message I'm getting indicates that it's likely it's trying to perform a mathematical or date function on a text field.
I took off the union part of this query statement and got a list of items in the combo box I just don't know what you're doing with the union part, is it solely so that you can get a 'null' option in your combo box?