Question

I’m having some trouble figuring out how construct a series of SQL statements to split some data I have into a per-year basis. There are n items which have a recorded quantity for a set of days across so many years. Here’s is a a small sample layout for the main data I have.

   |========|==============|===========|
   | Name   | Date         | Quantity  |
   |========|==============|===========|
 1 | AAAAA  | 10-DEC-2008  | 5         |
 2 | AAAAA  | 11-DEC-2008  | 2         |
 3 | AAAAA  | 12-DEC-2008  | 0         |
 4 | AAAAA  | 09-DEC-2009  | 3         |
 5 | AAAAA  | 10-DEC-2009  | 2         |
 6 | AAAAA  | 11-DEC-2009  | 3         |
 7 | BBBBB  | 10-DEC-2008  | 5         |
 8 | BBBBB  | 11-DEC-2008  | 2         |
 9 | BBBBB  | 12-DEC-2008  | 0         |
10 | BBBBB  | 09-DEC-2009  | 3         |
11 | BBBBB  | 10-DEC-2009  | 1         |
12 | BBBBB  | 11-DEC-2009  | 0         |
   |========|==============|===========|

I need to convert this into a table which takes the form.

   |========|==============|===============|===============|
   | Name   | Date         | Quantity 2008 | Quantity 2009 |
   |========|==============|===============|===============|
 1 | AAAAA  | 09-DEC       |               | 3             |
 2 | AAAAA  | 10-DEC       | 5             | 2             |
 3 | AAAAA  | 11-DEC       | 2             | 3             |
 4 | AAAAA  | 12-DEC       | 0             |               |
 5 | BBBBB  | 09-DEC       |               | 3             |
 6 | BBBBB  | 10-DEC       | 5             | 1             |
 7 | BBBBB  | 11-DEC       | 2             | 0             |
 8 | BBBBB  | 12-DEC       | 0             |               |
   |========|==============|===============|===============|

It should be assumed that there are thousands of named items in the database and the start days of recording on each year will be different, E.G., 6th Dec 2010 and 5th Dec 2009.

Hope someone can help.

Answer 1

In case you are using Oracle 11g, you can pivot the table as:

select *
  from (    
    select name,
           to_char(theDate, 'DD-MON') as dayMonth,
           extract(year from thedate) as year,
           quantity
      from yourTable
) 
 pivot (sum(quantity) as quantity for (year) in (2008 as y2008, 2009 as y2009))
order by name, dayMonth;

that returns the following

NAME  DAYMONTH        Y2008_QUANTITY         Y2009_QUANTITY         
----- --------------- ---------------------- ---------------------- 
AAAAA 09-DEC                                 3                      
AAAAA 10-DEC          5                      2                      
AAAAA 11-DEC          2                      3                      
AAAAA 12-DEC          0                                        
BBBBB 09-DEC                                 3                      
BBBBB 10-DEC          5                      1                      
BBBBB 11-DEC          2                      0                      
BBBBB 12-DEC          0                                           

8 rows selected