在Access 2010查询中使用IF THEN

Question

I'm not very knowledgeable in coding of Access queries, so I hope someone can help with this issue. I have a query (using the query builder) that has a field named RetrainInterval from table tblProcedures (this will return a number like 1, 3, 6, 12, etc.; the rotational months the particular document have to be retrained on) and another field named Training/Qualification Date from table tblTrainingRecords .

I want the query to look at the RetrainInterval for a given record (record field is ClassID in tblProcedures ) and then look at the Training/Qualification Date and calculate if that record should be in the query.

In a module I would do this:

IF RetrainInterval = 1 Then
DateAdd("m",1,[Training/Qualification Date]) <add to query if <=today()+30>
ElseIf RetrainInterval = 3 Then
DateAdd("m",3,[Training/Qualification Date]) <add to query if <=today()+30>
ElseIF......

How can I translate this into something that would work in a query? My end goal is to generate a report that will show me what document class numbers are due within a specified time interval (say I enter 30 in the form textbox to represent any upcoming required training within 30 days of the query), but all of the calculations to determine this is based off of when the last training date was (stored in the training records table). I also want to make sure that I do not get multiple returns for the same class number since there will be multiple training entries for each class, just grab the minimum last training date. I hope I explained it well enough. It's hard to put this into words on what I am trying to do without positing up the entire database.

UPDATE

I think I have simplified this a bit after getting some rest. Here are two images, one is the current query, and one is what comes up in the report. I have been able to refine this a bit, but now my problem is I only want the particular Class to show once on the report, not twice, even though I have multiple retrain due dates (because everything is looking at the table that holds the employee training data and will have multiple training's for each Class number). I would like to only show one date, the oldest. Hope that makes sense.

Query - http://postimg.org/image/cpcn998zx/

Report - http://postimg.org/image/krl5945l9/

Answer 1

When RetrainInterval = 1, you add 1 month to [Training/Qualification Date] .

When RetrainInterval = 3, you add 3 months to [Training/Qualification Date] .

And so on.

The pattern appears to be that RetrainInterval is the number of months to add. If that is true, use RetrainInterval directly in your DateAdd() expression and don't bother about IF THEN .

DateAdd("m", RetrainInterval, [Training/Qualification Date])

Answer 2

You can not do that in a query. Been there, cursed that!

You can use the IFF( 2>x ; 1 ;0) Giving that if the first statement is true, 1 is returned, and 0 if false. You can not return a criteria like IFF(2>x ; Cell>2 ; Cell>0) (Not possible) It will just return 0 if you try, i think. it will not give an error all the time.

You have to use criterias! I would to something like this picture:

I hope you follow, else let me know.