Perhitungan Biaya Rata-Rata Inventaris dalam SQL

Anda dapat menggunakan klausa MODEL untuk melakukan perhitungan rekursif ini

Buat tabel sampel dan masukkan data

create table costs (order_id int, volume int, price numeric(16,4), type char(1));

insert into costs (order_id, volume, price) values (1,1000,100);
insert into costs (order_id, volume, price) values (2,-500,110);
insert into costs (order_id, volume, price) values (3,1500,80);
insert into costs (order_id, volume, price) values (4,-100,150);
insert into costs (order_id, volume, price) values (5,-600,110);
insert into costs (order_id, volume, price) values (6,700,105);

Kueri (DIEDIT mengubah rules iterate(1000) untuk rules automatic order mengimplementasikan klausa MODEL seperti yang dimaksudkan untuk berfungsi, yaitu dari atas ke bawah secara berurutan. Itu juga membuat kueri dari 0,44 detik menjadi 0,01 detik!)

select order_id, volume, price, total_vol, total_costs, unit_costs
    from (select order_id, volume, price,
                 volume total_vol,
                 0.0 total_costs,
                 0.0 unit_costs,
                 row_number() over (order by order_id) rn
          from costs order by order_id)
   model
         dimension by (order_id)
         measures (volume, price, total_vol, total_costs, unit_costs)
         rules automatic order -- iterate(1000)
         ( total_vol[any] = volume[cv()] + nvl(total_vol[cv()-1],0.0),
           total_costs[any] =
                    case SIGN(volume[cv()])
                    when -1 then total_vol[cv()] * nvl(unit_costs[cv()-1],0.0)
                    else volume[cv()] * price[cv()] + nvl(total_costs[cv()-1],0.0)
                    end,
           unit_costs[any] = total_costs[cv()] / total_vol[cv()]
         )
   order by order_id

Keluaran

ORDER_ID VOLUME     PRICE      TOTAL_VOL   TOTAL_COSTS   UNIT_COSTS
1        1000       100        1000        100000        100
2        -500       110        500          50000        100
3        1500        80        2000        170000        85
4        -100       150        1900        161500        85
5        -600       110        1300        110500        85
6        700        105        2000        184000        92

Situs ini memiliki tutorial yang bagus tentang klausa MODEL

• http://www.sqlsnippets.com/en/topic-11663.html

    A         B       C      D          E                         F
 ---------------------------------------------------------------------------
1|  order_id  volume  price  total_vol  total_costs               unit_costs
2|                                   0                         0           0
3|  1           1000    100  =C4+E3     =IF(C4<0,G3*E4,F3+C4*D4)  =F4/E4
4|  2           -500    110  =C5+E4     =IF(C5<0,G4*E5,F4+C5*D5)  =F5/E5
5|  3           1500     80  =C6+E5     =IF(C6<0,G5*E6,F5+C6*D6)  =F6/E6
6|  4           -100    150  =C7+E6     =IF(C7<0,G6*E7,F6+C7*D7)  =F7/E7
7|  5           -600    110  =C8+E7     =IF(C8<0,G7*E8,F7+C8*D8)  =F8/E8
8|  6           700     105  =C9+E8     =IF(C9<0,G8*E9,F8+C9*D9)  =F9/E9