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Rownumber in Select - Partitioning

  • June 8, 2016 at 9:43 am

    #326859

    Hello, I have a table that I want to add a rownumber to.

    I want to partition the row numbers but the PARTITION key word in the ROWNUMBER() function is sort of doing the opposite of what I really want.

    I have a table with a "Code" field. The Codes can be repeated but sometimes there is just 1 of them.

    So, I would like the results to be like this:

    RowNum Code

    1 AB10003

    2 RG42421

    2 RG42421

    2 RG42421

    3 DG31311

    etc...

    So, every unique code should get a new row number but if it finds the same code more than once I'd like it to tag the same row number to it.

    Is there a clever way to do this?

    Thanks!

  • June 8, 2016 at 9:57 am

    #1883918

    You might be over complicating things...is this what you want?

    DECLARE @myTable TABLE (Code VARCHAR(7))

    INSERT INTO @myTable

    VALUES ('AB10003'), ('RG42421'), ('RG42421'), ('RG42421'), ('DG31311')

    SELECT DENSE_RANK() OVER (ORDER BY Code) AS RowNum, Code FROM @myTable

    SELECT quote FROM brain WHERE original = 1
    0 rows returned

  • June 8, 2016 at 10:50 am

    #1883945

    I think yb751 has the right answer. However, maybe you should consider a better name than calling it RowNum. In this case maybe something like CodeNum would be better. It might pedantic but names are very important. I know I would be horribly confused by the name RowNum the way you are using it. But something like CodeNum is immediately clear what it means.

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  • June 8, 2016 at 12:30 pm

    #1883998

    LOL you're right I was over complicating it... DENSE_RANK worked just peachy.... I admit I didn't know about the dense_rank function ... *blush*

    Don't worry, those aren't the actual names of my fields... I was just making that up for the post. 🙂

  • June 8, 2016 at 12:55 pm

    #1884006

    amy26 (6/8/2016)

    LOL you're right I was over complicating it... DENSE_RANK worked just peachy.... I admit I didn't know about the dense_rank function ... *blush*

    Don't worry, those aren't the actual names of my fields... I was just making that up for the post. 🙂

    No problem, I'm glad it worked for you.

    Cheers,

    SELECT quote FROM brain WHERE original = 1
    0 rows returned

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