Question

I have a following table.

ID Name State Date
1   A1   First 1/10/2013
2   A1   Second 1/11/2013
3   A1   Last   1/12/2013
4   A2   First  1/10/2013
5   A2   Closed 1/11/2013
6   A3   First  1/10/2012
7   A3   Second 1/10/2012

The order of preference of state is as follows

 1 First
 2 Second
 3 Last
 4 Closed

Which means that I have to display only the latest state of the Name (provided the state is not closed. In case the state is closed, I do not have to display that ID).

So the output of the above table should be

ID Name State Date
3  A1    Last  1/12/2013
7  A3    Second 1/10/2012

I’m not sure how to proceed? I would have tried something had I’d known but for now I’m struggling with it. I can do this in php and store the output in another table/view and display it but it has to be done in the database.

Thanks

Answer 1

Assuming that your ID is auto_incremented.

SELECT  a.*
FROM    tableName a
        INNER JOIN
        (
            SELECT  name, MAX(ID) max_ID
            FROM    tableName
            GROUP   BY Name
        ) b ON  a.ID = b.max_ID AND
                a.Name = b.Name
WHERE   a.State <> 'Closed'

or if the datatype of column date is DATE

SELECT  a.*
FROM    tableName a
        INNER JOIN
        (
            SELECT  name, MAX(date) max_date
            FROM    tableName
            GROUP   BY Name
        ) b ON  a.ID = b.max_date AND
                a.Name = b.Name
WHERE   a.State <> 'Closed'