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Return just a sample of the code

  • July 13, 2004 at 6:12 pm

    #109091

    I'm in the process of running a very large join, and I'm not sure if this will run the way I want it to.  But before I run this t-sql statement I would like to see a sample what what my code will return to me (maybe the first 10 lines).  I would assume that TOP would only give me whatever percent or top 10 that I'm asking for.  All I really want to do is make sure that what I have written is truly what I want?  Can you please help and show some type of example or point me in the right direction for BOL..  TIA

  • July 13, 2004 at 8:08 pm

    #514489

    You have answered your own question!

    Just do a TOP 10

    As you have stated above, "maybe the first 10 lines", the TOP Clause is what you need!

    Kindest Regards,

  • July 13, 2004 at 10:43 pm

    #514497

    select top 10

    will give you the first 10 rows (and the specific rows which are returned depend on any ORDER BY clause in your query).

    Eg, perhaps you want to see the 10 most recent records added to a table:

    select top 10 *

    from table

    order by ID desc

    will work if the table.ID field is an incrementing field.

    select top 10 percent *

    from table

    order by ID desc

    works in a similar way, except the number of rows returned is 10% of the total in the underlying recordset. I've found this to be a useful way of sampling large volumes of data - in conjunction with putting something (quasi) random in the ORDER BY clause.

    If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.

  • July 14, 2004 at 4:04 pm

    #514562

    true - but - does that not still go out and scan the whole table or should I assume w/TOP the scan will only exe the syntax on the first ten records or 10 percent. Which would work best TOP or ROWCOUNT() thoughts...

  • July 14, 2004 at 5:45 pm

    #514572

    Alternatively, just limit the result set in your WHERE Clause!

    Kindest Regards,

  • July 14, 2004 at 5:49 pm

    #514573

    Please explain!

  • July 14, 2004 at 6:57 pm

    #514584

    BOL suggests that TOP should be used:

    "It is recommended that DELETE, INSERT, and UPDATE statements currently using SET ROWCOUNT be rewritten to use the TOP syntax. For more information, see DELETE, INSERT, or UPDATE."

    If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.

  • July 14, 2004 at 7:15 pm

    #514585

    "BOL suggests that TOP should be used:"

    "It is recommended that DELETE, INSERT, and UPDATE statements currently using SET ROWCOUNT be rewritten to use the TOP syntax. For more information, see DELETE, INSERT, or UPDATE."

    SELECT is not there So, it is safe to use rowcount for read only operations.

     

     


    * Noel

  • July 14, 2004 at 7:55 pm

    #514587

    Jeez, perhaps I had one-too-many beers last night. Well spotted and I think I'll keep quiet for a while!

    If you haven't even tried to resolve your issue, please don't expect the hard-working volunteers here to waste their time providing links to answers which you could easily have found yourself.

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