正確的數據庫模式

Question

select sum(c.cost) 
from (select x.num as x, y.num as y, max(priority) as maxpriority 
     from numbers x cross join 
      numbers y join 
      costs c 
      on x.num between c.x and c.x + c.deltax and y.num between c.y and c.y + c.deltay 
     where x.value between PIXELX and PIXELX and DELTAX and 
      y.value between PIXELY and PIXELY and DELTAY 
     group by x.num, y.num 
    ) xyp join 
    costs c 
    on xyp.x between c.x and c.x + c.deltax and xyp.y between c.y + c.deltay and 
     xyp.maxpriority = c.priority 

我已經給出了這個答案，當在一個數據庫中的兩個點之間尋找一個「成本」時，每個區域都有不同的成本。我一直試圖讓這一起找出數據庫架構的工作，目前我得到#1054 - Unknown column 'x.value' in 'where clause'與

Name Type Collation Attributes Null Default Extra Action 
    1 num int(11)   No None   Change  Drop Browse distinct values  More 

數字和

# Name Type Collation Attributes Null Default Extra Action 
1 x int(11)   No None   Change  Drop Browse distinct values  More 
2 y int(11)   No None   Change  Drop Browse distinct values  More 
3 deltax int(11)   No None   Change  Drop Browse distinct values  More 
4 deltay int(11)   No None   Change  Drop Browse distinct values  More 
5 priority int(11)   No None   Change  Drop Browse distinct values  More 

的成本。一直試圖弄清楚這一點，非常感謝任何人爲指針。

編輯：好吧它現在不會拋出錯誤，但它返回null而不是選定區域內的成本。

Answer 1

您的numbers表沒有名爲value的列，您試圖引用不存在的列，因此出現錯誤。您當前的代碼：

where x.value between PIXELX and PIXELX and DELTAX and 

我猜測你想使用num代替：

where x.num between PIXELX and PIXELX and DELTAX and 
     y.num between PIXELY and PIXELY and DELTAY