MS-Access : Query to generate dates for recurring events?

问题

I'm not too familiar with the more complex queries and I'm having an issue finding some examples to take apart to utilize..

Event Name  | Due Date   | Frequency    |Frequency UOM
S-XYC-001   | 10/17/2020 |  360         |    D
S-XYA-003   | 6/1/2020   |  90          |    D
S-XYC-004   | 4/3/2020   |  180         |    D

So, we have a set of work that has an initial due date provided, and an expected frequency along with a unit of measurement (I've converted all my frequencies into days as there was previously a mix of days, quarterlies, months..).

I've been asked to generate a forecast of events in 2020. So, using the above source table we'd expect our list to look like this:

Event Name  | Due Date   | Frequency    | Frequency UOM
S-XYC-001   | 10/17/2020 |  360         |     D
S-XYA-003   | 6/1/2020   |  90          |     D
S-XYA-003   | 8/30/2020  |  90          |     D
S-XYA-003   | 11/28/2020 |  90          |     D
S-XYC-004   | 4/3/2020   |  180         |     D
S-XYC-004   | 9/30/2020  |  180         |     D

I'm really not quite sure what type of query to apply to get these results, Or honestly what to look for to get some examples I can utilize to do what I need to.

回答1:

First, change your frequency to months - 12, 3, and 6 respectively - to obtain the correct result dates.

Then, create a small query and save it as Ten as it simply returns 0 to 9:

SELECT DISTINCT 
    Abs([id] Mod 10) AS N
FROM 
    MSysObjects;

Use that in this generic query that is capable of generating any sequence of date/time in the entire range of DateTime:

PARAMETERS 
    [Interval] Text ( 255 ), 
    [Number] IEEEDouble, 
    [Date] DateTime, 
    [Count] IEEEDouble;
SELECT 
    [Ten_0].[N]+[Ten_1].[N]*10+[Ten_2].[N]*100+[Ten_3].[N]*1000+[Ten_4].[N]*10000+[Ten_5].[N]*100000+[Ten_6].[N]*1000000+[Ten_7].[N]*10000000 AS Id, 
    DateAdd([Interval],Fix([Number])*([Ten_0].[N]+[Ten_1].[N]*10+[Ten_2].[N]*100+[Ten_3].[N]*1000+[Ten_4].[N]*10000+[Ten_5].[N]*100000+[Ten_6].[N]*1000000+[Ten_7].[N]*10000000),[Date]) AS [Date]
FROM 
    Ten AS Ten_0, 
    Ten AS Ten_1, 
    Ten AS Ten_2, 
    Ten AS Ten_3, 
    Ten AS Ten_4, 
    Ten AS Ten_5, 
    Ten AS Ten_6, 
    Ten AS Ten_7
WHERE 
    ((([Ten_0].[N]+[Ten_1].[N]*10+[Ten_2].[N]*100+[Ten_3].[N]*1000+[Ten_4].[N]*10000+[Ten_5].[N]*100000+[Ten_6].[N]*1000000+[Ten_7].[N]*10000000)<[Count]) 
    AND 
    (([Interval]) In ("s","n","h","d","w","ww","m","q","yyyy")) 
    AND 
    ((Fix([Number])*([Ten_0].[N]+[Ten_1].[N]*10+[Ten_2].[N]*100+[Ten_3].[N]*1000+[Ten_4].[N]*10000+[Ten_5].[N]*100000+[Ten_6].[N]*1000000+[Ten_7].[N]*10000000) Mod IIf(Fix([Number])=0,1,Fix([Number])))=0) 
    AND 
    ((Ten_0.N)<=[Count]\1) 
    AND 
    ((Ten_1.N)<=[Count]\10) 
    AND 
    ((Ten_2.N)<=[Count]\100) 
    AND 
    ((Ten_3.N)<=[Count]\1000) 
    AND 
    ((Ten_4.N)<=[Count]\10000) 
    AND 
    ((Ten_5.N)<=[Count]\100000) 
    AND 
    ((Ten_6.N)<=[Count]\1000000) 
    AND 
    ((Ten_7.N)<=[Count]\10000000));

Save it as DatesSequence.

This you can run with the parameters:

Interval: "m"
Number: 3, 6, or 12
Date: Due Date
Count: The count of future event dates to list

Results:

You could modify the query to filter out dates later than 2020.

来源：https://stackoverflow.com/questions/59494027/ms-access-query-to-generate-dates-for-recurring-events

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ms-access