每天的SQL计数状态

Question

Fairly new to SQL, but I am looking for help with organizing some data. Have several status broken out into different columns with date/time and want to be able to pivot them to give a breakdown of the different status on each day.

For instance the following data:

 Status4            Status5             Status6             Status7
 12/1/17 5:46       NULL                NULL                NULL
 11/30/17 14:53     11/30/17 14:53      11/30/17 14:53      11/30/17 14:54
 11/18/17 4:50      11/18/17 4:48       11/18/17 4:48       NULL    

Would return a table such as the one below with the bounds of highest and lowest date present in Status4.

               Status4      Status5     Status6     Status7
 11/18/17          1           1           1        0
 11/30/17          2           2           2        1
 12/1/1            3           2           2        1

Thanks!

Answer 1

If you are looking at getting counts against each date, try this code.
Please note you have to write a dynamic query, if number of status columns is dynamic / unknown.

DECLARE @TempDates As Table (DateValues Date)

/*Table1 is the table having your status columns */
Insert into @TempDates
    Select Convert(Date,Status1) from Table1
    Union 
    Select Convert(Date,Status2) from Table1
    Union 
    Select Convert(Date,Status3) from Table1
    Union
    Select Convert(Date,Status4) from Table1

    SELECT * FROM 
             (
                 SELECT COL, VAL, DateValues FROM Table1
                 CROSS APPLY (VALUES (Convert(Date,Status1),'Status1'),
                                      (Convert(Date,Status2),'Status2'),
                                      (Convert(Date,Status3),'Status3'),
                                      (Convert(Date,Status4),'Status4')) CS (COL,VAL)
                RIGHT JOIN @TempDates tp ON tp.DateValues = CS.COL
            )T
            PIVOT 
            ( 
                    COUNT(COL)
                    FOR VAL in ([Status1],[Status2],[Status3],[Status4])
            ) P
            WHERE Datevalues IS NOT NULL