我有四张桌子，需要帮助每张桌子的每张价格总和
1表skom
_________________________________
| id | noskom | price_skom |
|____|_____________|____________|
| 1 | 1 | 10 |
| 2 | 2 | 30 |
|__3_|_3___________|___50_______|
2表skop
______________________________________________
| id | noskom | noskop | price_skop |
|____|_____________|____________|____________|
| 1 | 1 | 1 | 10 |
| 2 | 1 | 2 | 20 |
| 3 | 2 | 3 | 5 |
| 4 | 2 | 4 | 30 |
|____|_____________|____________|____________|
3表npbm
___________________________________________________________
| id | noskom | noskop | nonpbm | price_npbm |
|____|_____________|____________|____________|____________|
| 1 | 1 | 1 | 1 | 10 |
| 2 | 1 | 1 | 2 | 20 |
| 3 | 1 | 2 | 3 | 5 |
| 4 | 1 | 2 | 4 | 5 |
| 5 | 2 | 1 | 5 | 10 |
| 6 | 2 | 2 | 6 | 10 |
| 7 | 2 | 2 | 7 | 10 |
|____|_____________|____________|____________|____________|
4表npbp
________________________________________________________________________
| id | noskom | noskop | nonpbm | nonpbp | price_npbp |
|____|_____________|____________|____________|____________|____________|
| 1 | 1 | 1 | 1 | 1 | 10 |
| 2 | 1 | 1 | 2 | 2 | 20 |
| 3 | 1 | 2 | 3 | 3 | 5 |
| 4 | 1 | 2 | 4 | 4 | 5 |
| 5 | 2 | 1 | 5 | 5 | 10 |
| 6 | 2 | 2 | 6 | 6 | 10 |
| 7 | 2 | 2 | 7 | 10 | 10 |
|____|_____________|____________|____________|____________|____________|
我需要像这样的查询帮助
select sum(price_skom),sum(price_skop),sum(price_npbm),sum(price_npbp) from each table group by noskom
我想要这样的结果
表结果分组依据noskom
________________________________________________________________
| id | noskom | sum_skom | sum_skop | sum_npbm | sum_npbp |
|____|_____________|__________|__________|__________|__________|
| 1 | 1 | 10 | 30 | 40 | 90 |
| 2 | 2 | 30 | 35 | 30 | 70 |
|__3_|_3___________|___50_____|__________|__________|__________|
帮我解决mysql查询
答案 0 :(得分：1)
要获得没有相应noscom的行，您需要有一个外部联接：
select sk1.id, sk1.noskom,sum(price_skom),sum(price_skop),sum(price_npbm),sum(price_npbp)
from skom sk1 left outer join skop on (sk1.id=skop.noskom),
skom sk2 left outer join npbm on (sk2.id=npbm.noskom),
skom sk3 left outer join npbp on (sk3.id=npbp.noskom)
Where sk1.id=sk2.id and sk2.id=sk3.id
group by sk1.id,sk1.noskom
答案 1 :(得分：1)
这样的事情：
select
noskom,
sum (pskom) as sum_skom,
sum (pskop) as sum_skop,
sum (pnpbm) as sum_npbm,
sum (pnpbp) as sum_npbp
from
(
select noskom, sum (price_skom) as pskom, 0 as pskop, 0 as pnpbm, 0 as pnpbp from skom group by noskom
union all
select noskom, 0, sum (price_skop), 0, 0 from skop group by noskom
union all
select noskom, 0, 0, sum (price_npbm), 0 from npbm group by noskom
union all
select noskom, 0, 0, 0, sum (price_npbp) from npbp group by noskom
) as p
group by noskom