Group By - question

  • I have a question which is probably really basic but can't work it out for the life of me so i thought i'll ask for some help. Below is a rough sketch of how my database is there are more details but principle is the same.

    In my database i have a table called "Meetings" & in my query i want to group all my meetings that are possible such as below.

    DATE | TypeOfMeeting | NameOfMeeting

    20120801 private Review

    20120801 private Review

    20120801 group Review

    20120801 group Review

    20120801 group Review

    20120801 Conference Call Review

    20120801 Conference Call Review

    SELECT

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    FROM

    dbo.meetings

    GROUP BY

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    Only thing is in "TypeOfMeeting" i have the options of

    - Group

    - Conference Call

    - Private

    I want to group all the meetings except "Private" so if i have the same Date,TypeOfMeeting,NameofMeeting for Group or Conference Call they should all be groups for people involved. However if its Private then it should not be grouped and all the Private meetings should be seperated.

    So the expected result should be:

    DATE | TypeOfMeeting | NameOfMeeting

    20120801 private Review

    20120801 private Review

    20120801 group Review

    20120801 Conference Call Review

    How do i ignore private from the group by results?

  • Update:

    I got around the issue by just doing a quick fix, just made 2 seperate scripts one to only be "Private" and one to exclude only "Private" in my where condition.

    I'm Not to worried about the permanent fix to my problem as it was a once off so thats fine, but would like to know for future reference if that is possible to achieve what has been requested or seperate scripts is the only way to go.

  • Not exactly sure that I follow your requirements, but it sounds like you could use UNION to combine two data sets, one with a GROUP BY and one without. You're not including any aggregate logic in your select, so I assume that in this instance you're using GROUP BY to achieve the same effect as DISTINCT and avoid repeated rows in the non-private list of meetings (??).

    SELECT

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    FROM

    dbo.meetings

    WHERE

    [TypeofMeeting] = 'private'

    UNION ALL

    SELECT

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    FROM

    dbo.meetings

    WHERE

    [TypeofMeeting] <> 'private'

    GROUP BY

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

  • This should do what you want:

    --I have a question which is probably really basic but can't work it out for the life of me so i thought i'll ask for some help. Below is a rough sketch of how my database is there are more details but principle is the same.

    --In my database i have a table called "Meetings" & in my query i want to group all my meetings that are possible such as below.

    --========= TEST DATA =============

    declare @Meetings table ([DATE] Char(8), TypeOfMeeting Varchar(20), NameOfMeeting Varchar(10));

    insert @Meetings values ( '20120801', 'private', 'Review' );

    insert @Meetings values ( '20120801', 'private', 'Review' );

    insert @Meetings values ( '20120801', 'group', 'Review' );

    insert @Meetings values ( '20120801', 'group', 'Review' );

    insert @Meetings values ( '20120801', 'group', 'Review' );

    insert @Meetings values ( '20120801', 'Conference Call', 'Review' );

    insert @Meetings values ( '20120801', 'Conference Call', 'Review' );

    select * from @Meetings;

    /*

    DATE | TypeOfMeeting | NameOfMeeting

    20120801 private Review

    20120801 private Review

    20120801 group Review

    20120801 group Review

    20120801 group Review

    20120801 Conference Call Review

    20120801 Conference Call Review

    */

    --========= SOLUTION =============

    -- Use 2 selects, 1 grouped for [TypeofMeeting] <> 'private',

    -- & 1 not grouped for [TypeofMeeting] = 'private', & UNION them together.

    -- NOTE: You MUST use UNION ALL, or duplicate rows are removed from the result set -

    -- so only 1 'private' would appear.

    SELECT

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    FROM

    @meetings

    WHERE [TypeofMeeting] <> 'private'

    GROUP BY

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    UNION ALL

    SELECT

    [DATE],

    [TypeofMeeting],

    [NameofMeeting]

    FROM

    @meetings

    WHERE [TypeofMeeting] = 'private'

    /*

    Only thing is in "TypeOfMeeting" i have the options of

    - Group

    - Conference Call

    - Private

    I want to group all the meetings except "Private" so if i have the same Date,TypeOfMeeting,NameofMeeting

    for Group or Conference Call they should all be groups for people involved. However if its Private

    then it should not be grouped and all the Private meetings should be seperated.

    So the expected result should be:

    DATE | TypeOfMeeting | NameOfMeeting

    20120801 private Review

    20120801 private Review

    20120801 group Review

    20120801 Conference Call Review

    How do i ignore private from the group by results?

    */

  • Thanks guys, I didn't even think about using a union which was pretty simple idea. I was trying all other stuff.

    In terms of my whole process - it probably is easier running 2 separate scripts. Because its quiet a detailed process and easier to troubleshoot / investigate running it separately.

    But going forward if I have an issue like this on a non-complex script then union would be way to go.

    Thanks again

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