更新与同桌

Question

百分比计算研究我有一个这样的表：

ItemID  PersonID Score  Percentage 
========================================== 
1    1  10   [ = 10/10+30 = 25%] 
1    2  30   [ = 30/10+30 = 75%] 
2    1  20   [ = 20/20+40 = 33%] 
2    2  40   [ = 40/20+40 = 67%] 

的“百分比”中的数据没有进入，但是自动计算的，在一定的时间间隔。 计算是百分比=分数/总项目ID分数

而不是使用“选择做数学更新”方法，我试图编写单个SQL来更新“百分比”。

我想什么是这样的：

UPDATE tb_temp AS t1 
    SET t1.Percentage = 
     CEIL(t1.Score/
      (SELECT SUM(t2.Score) FROM tb_temp AS t2 WHERE t2.ItemID = t1.ItemID) 
     ); 

但它不工作（错误代码：1093你不能指定FROM子句中更新目标表“T1”）。

有什么想法？

Answer 1

尝试：

UPDATE tb_temp t1 
    JOIN (SELECT ItemId, SUM(t2.Score) TotalScore 
      FROM tb_temp 
      group by ItemId) t2 ON t2.ItemID = t1.ItemID 
    SET t1.Percentage = CEIL(t1.Score/t2.TotalScore) 

Answer 2

UPDATE tb_temp AS t1 
    SET t1.Percentage = 
     CEIL(t1.Score/
      (SELECT SUM(t2.Score) FROM tb_temp AS t2 left join tb_temp AS t3 on t2.ItemID = t3.ItemID) 
     );