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  1. #1
    Join Date
    Dec 2011
    Posts
    82

    Unanswered: Penultimate date from a list

    Hello

    I am very new to informix and am looking for some help

    I need to know how to find the right syntex to find the penultimate date from a list

    I can find the maximum date: Select MAX(datetime) maximum_date

    I am thinking that i need to use the MAX function again to find the penultimate date from the same list but am unsure of the correct way to right it

    Would I write it in the Select statement as something like MAX(datetime)-1?

    Does anyone have any ideas?

    Thanks
    Helen

  2. #2
    Join Date
    Nov 2010
    Posts
    16
    Insteresting question...
    First, do you know how to do it on any other database?
    And what happens if there are two equal dates? For example:

    2011-12-15 09:00:00
    2011-12-15 09:00:00
    2011-12-14 09:00:00

    Which one should be returned? Or is this scenario impossible? If in the example above the last row would be selected, than another subquery selecting the max(date_field) ... WHERE date_field < (select max(date_field) could be used (although I fear for the performance)

    Regards

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