在mySQL中使用SUM（）和UNION ALL来获取多个sum列

Question

我有四个表，所有表都包含以下列：
'地点'
'sortiment'
'amount_in'（数字）
'amount_out'（数字）

所有这些都代表了木材加工的不同情况，例如生产，储存，铁路车辆装载等，仅供参考。使用不同的SUM（in-out）查询，我可以看到每个位置中不同木材分拣的数量。但是，每次添加新位置时，我都必须手动添加新查询，例如新的日志记录区域。基本上这些表都是相似的，所以我可以使用UNION ALL来总结所有地方！

现在我想做的是创建一个包含单个查询的表，基本上看起来像这样：

|             | location A | location B | location C |
|-------------|------------|------------|------------|
| sortiment A |  sum(AA)   |  sum(AB)   |  sum(AC)   |
| sortiment B |  sum(BA)   |  sum(BB)   |  sum(BC)   |
| sortiment C |  sum(CA)   |  sum(CB)   |  sum(CC)   |

所有表都包含所有排序，但每个表都有不同的位置。

这是我先试过的：

SELECT location, sortiment, SUM(amount_in-amount_out)
FROM (
SELECT location, sortiment, amount_in, amount_out FROM Eproduction 
UNION ALL
SELECT location, sortiment, amount_in, amount_out FROM Estorage 
UNION ALL
SELECT location, sortiment, amount_in, amount_out FROM Elogdepot
UNION ALL
SELECT location, sortiment, amount_in, amount_out FROM Erailway
) x
GROUP by location";

然后循环

echo "<tr><td>".$row['sortiment']. "</td><td>" .(float)$row['SUM(amount_in-amount_out)']."</td></tr>";

显然导致了这个

| sortiment A | sum(AA) |
| sortiment B | sum(BA) |
| sortiment C | sum(CA) |
| sortiment A | sum(AB) |
| sortiment B | sum(BB) |
| sortiment C | sum(CB) |etc

这不是我想要达到的目标。

然后我尝试了别名：

SELECT location, sortiment, 
SUM(in_pr-out_pr), 
SUM(in_sto-out_sto), 
SUM(in_log-out_log), 
SUM(in_rail-out_rail)
FROM (
SELECT location, sortiment, amount_in AS in_pr, amount_aout AS out_pr FROM Eproduction 
UNION ALL
SELECT location, sortiment, amount_in AS in_sto, amount_out AS out_sto FROM Estorage 
UNION ALL
SELECT location, sortiment, amount_in AS in_log, amount_out AS out_log FROM Elogdepot
UNION ALL
SELECT location, sortiment, amount_in AS in_rail, amount_out AS out_rail FROM Erailway
) x
GROUP by location, sortiment";

然后循环

echo "<tr><td>".$row['location']. "</td><td>".$row['sortiment']. "</td><td>" .(float)$row['SUM(in_pr-out_pr)']."</td><td>" .(float)$row['SUM(in_sto-out_sto)']."</td><td>" .(float)$row['SUM(in_log-out_log)']."</td><td>" .(float)$row['SUM(in_rail-out_rail)']."</td></tr>";

在我的理解中应该创建我想要的表，但是它会返回'unknown field'in_sto''错误。

任何帮助表示感谢，提前谢谢！