sql查詢找到總百分比

Question

SELECT tblItems.ItemType, Count(tblItems.ItemType) AS total 
FROM tblItems 
WHERE (((tblItems.Pool) BETWEEN 188 AND 218)) 
GROUP BY tblItems.ItemType; 

這是我當前的查詢，它打印出一行中的項目以及它們出現在另一行命名爲total的總時間。我希望能夠用這個百分比表示總行數。我試圖在(total/SUM(total)) AS pct_total之後添加，但這不起作用。我得到的錯誤是

Answer 1

這裏有一個方法：

SELECT i.ItemType, Count(i.ItemType) AS total, 
     Count(*) * 1.0/(select count(*) from tblItems WHERE Pool between 188 and 218) as ratio 
FROM tblItems as i 
WHERE i.Pool BETWEEN 188 AND 218 
GROUP BY i.ItemType; 

Answer 2

您可能需要使用子查詢..嘗試這樣的「子查詢不能在表達式（總和（總））使用」：

select Itemtype,(total/SUM(total)) AS pct_total from 
(SELECT tblItems.ItemType as Itemtype, Count(tblItems.ItemType) AS total 
FROM tblItems 
WHERE (((tblItems.Pool) BETWEEN 188 AND 218)) 
GROUP BY tblItems.ItemType) as A 
Group By A.Itemtype;