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query

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databasetutorial
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  • G Guffa

    For example when you have a sub query. In that case the fields are specified in the sub query and doesn't need to be repeated in the query.

    select *
    from (
    select top 10 SomeField, AnotherField
    from SomeTable
    order by SomeField asc
    ) x
    order by SomeField desc

    Despite everything, the person most likely to be fooling you next is yourself.

    H Offline
    H Offline
    Harvey Saayman
    wrote on last edited by
    #9

    okay that makes sense, cause your just selecting everything returned from the sub query...

    Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

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    • H Harvey Saayman

      J4amieC wrote:

      circa 1997

      I was 9 back then ;P Its just a practice i was taught and it stuck, and if these newbies get used to SELECT * FROM and they one day work on or with big databases (like the systems you'll come across at the data warehouse of an insurance company) they will bring it down! Ive heard about things like this being common from my step mom who's a data modeler.

      Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

      J Offline
      J Offline
      J4amieC
      wrote on last edited by
      #10

      Harvey Saayman wrote:

      I was 9 back then

      I know you were, ow stop making me feel old!

      Harvey Saayman wrote:

      they will bring it down

      bring it down how? Essentially nowdays Select * is identical to select col1,col2...

      H 1 Reply Last reply
      0
      • H Harvey Saayman

        Ashfield wrote:

        and yes, there are times when you need to do it

        like when? :doh:

        Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

        A Offline
        A Offline
        Ashfield
        wrote on last edited by
        #11

        A simple example, when you are extracting a subset of data to a file for any reason. As I said, not the normal run of the mill applications, and I agree you shouldn't use it normally, but, as they say, never say never :)

        Bob Ashfield Consultants Ltd

        C 1 Reply Last reply
        0
        • J J4amieC

          Harvey Saayman wrote:

          I was 9 back then

          I know you were, ow stop making me feel old!

          Harvey Saayman wrote:

          they will bring it down

          bring it down how? Essentially nowdays Select * is identical to select col1,col2...

          H Offline
          H Offline
          Harvey Saayman
          wrote on last edited by
          #12

          J4amieC wrote:

          I know you were, now stop making me feel old!

          bwhahahaha, sorry... :laugh:

          J4amieC wrote:

          bring it down how?

          SELECT *
          FROM table1
          JOIN table2
          ON someCondition
          JOIN table3
          ON someOtherCondition

          If you pull that kinda crap (and sadly it happens) on DB's containing terra's upon terra's of data...

          Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

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          • H Harvey Saayman

            J4amieC wrote:

            I know you were, now stop making me feel old!

            bwhahahaha, sorry... :laugh:

            J4amieC wrote:

            bring it down how?

            SELECT *
            FROM table1
            JOIN table2
            ON someCondition
            JOIN table3
            ON someOtherCondition

            If you pull that kinda crap (and sadly it happens) on DB's containing terra's upon terra's of data...

            Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

            J Offline
            J Offline
            J4amieC
            wrote on last edited by
            #13

            Ok, I see your point, but its not the * thats the issue its the pulling of all fields from a large query. Someone stupid enough to do that would follow your advice and just write:

            SELECT [very long list of column names]
            FROM table1
            JOIN table2
            ON someCondition
            JOIN table3
            ON someOtherCondition

            Now leave me in peace you little whipper-snapper.

            H 1 Reply Last reply
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            • J J4amieC

              Ok, I see your point, but its not the * thats the issue its the pulling of all fields from a large query. Someone stupid enough to do that would follow your advice and just write:

              SELECT [very long list of column names]
              FROM table1
              JOIN table2
              ON someCondition
              JOIN table3
              ON someOtherCondition

              Now leave me in peace you little whipper-snapper.

              H Offline
              H Offline
              Harvey Saayman
              wrote on last edited by
              #14

              J4amieC wrote:

              Now leave me in peace you little whipper-snapper.

              lol, i had to go google [define:"whipper snapper"] :laugh: cheers bud

              Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

              J 1 Reply Last reply
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              • H Harvey Saayman

                J4amieC wrote:

                Now leave me in peace you little whipper-snapper.

                lol, i had to go google [define:"whipper snapper"] :laugh: cheers bud

                Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

                J Offline
                J Offline
                J4amieC
                wrote on last edited by
                #15

                damn, after doing that it soudsn kinda insulting. I didn't mean it that way. :|

                H 1 Reply Last reply
                0
                • J J4amieC

                  damn, after doing that it soudsn kinda insulting. I didn't mean it that way. :|

                  H Offline
                  H Offline
                  Harvey Saayman
                  wrote on last edited by
                  #16

                  its all good, didn't think you did

                  Harvey Saayman - South Africa Junior Developer .Net, C#, SQL you.suck = (you.Passion != Programming & you.Occupation == jobTitles.Programmer) 1000100 1101111 1100101 1110011 100000 1110100 1101000 1101001 1110011 100000 1101101 1100101 1100001 1101110 100000 1101001 1101101 100000 1100001 100000 1100111 1100101 1100101 1101011 111111

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                  • A Ashfield

                    A simple example, when you are extracting a subset of data to a file for any reason. As I said, not the normal run of the mill applications, and I agree you shouldn't use it normally, but, as they say, never say never :)

                    Bob Ashfield Consultants Ltd

                    C Offline
                    C Offline
                    Colin Angus Mackay
                    wrote on last edited by
                    #17

                    Ashfield wrote:

                    when you are extracting a subset of data to a file for any reason

                    Including when I only want a subset of the columns?

                    Recent blog posts: *SQL Server / Visual Studio install order *Installing SQL Server 2005 on Vista *Crazy Extension Methods Redux * Mixins My Blog

                    A 1 Reply Last reply
                    0
                    • C Colin Angus Mackay

                      Ashfield wrote:

                      when you are extracting a subset of data to a file for any reason

                      Including when I only want a subset of the columns?

                      Recent blog posts: *SQL Server / Visual Studio install order *Installing SQL Server 2005 on Vista *Crazy Extension Methods Redux * Mixins My Blog

                      A Offline
                      A Offline
                      Ashfield
                      wrote on last edited by
                      #18

                      Not really, I was replying t a cmment that said NEVER use select *

                      Bob Ashfield Consultants Ltd

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