Cross Tab - Storing different dates (Meeting1, Meeting2, Meeting 3 etc) in the same column

Question

I need to keep track of different dates (dynamic). So for a specific Task you could have X number of dates to track (for example DDR1 meeting date, DDR2 meeting date, Due Da

Answer 1

Version-1: +simple, -must be changed every time DateType is added. So is not great for a dynamic solution:

SELECT      tt.ID,
            tt.TaskDescription,
            td1.Date AS DDR1,
            td2.Date AS DDR2,
            td3.Date AS DueDate
FROM        Tasks tt
LEFT JOIN   Tasks_DateType td1
        ON  td1.TasksID = tt.ID AND td1.DateTypeID = 1
LEFT JOIN   Tasks_DateType td2
        ON  td2.TasksID = tt.ID AND td2.DateTypeID = 2
LEFT JOIN   Tasks_DateType td3
        ON  td3.TasksID = tt.ID AND td3.DateTypeID = 3

Version-2: completely dynamic (with some limitations, but they can be handled - just google for it):

Dynamic pivot query creation. See Dynamic Cross-Tabs/Pivot Tables: you need to create one SP of UDF and then can use it for multiple purposes. This is the original post, to which you may find many links and improvements.

Version-3: just leave it for your client code to handle. I would not design my SQL to return a dynamic set of data, but rather handle it on the client (presentation layer). I just would not like to handle some dynamic columns that come as a result of my query, where I need to guess what is that exactly. The only reason I use Version-2 is when the result is presented directly as a table for a report. In all other cases for truly dynamic data I use client code. For example: having structure you have, how will you attach logic that field DueDate is mandatory - you cannot use DB constraints; how will you ensure that DDR1 is not higher then DDR2? If these are not separate (static) columns in the database (where you can use CONSTRAINTS), then the client code is the one that validates your data consistency.

Good luck!