SQL获取SQL查询中每个项的计数

Question

我有这个表

<表类> ID PhoneID PhoneName 活动 状态 tbody><<tr>111121b0232c1142d1152e0363f1173g td> 1183h1194我04104j11

您可以使用返回每个PhoneID的计数的子查询来完成此操作:

SELECT t.ID, t.PhoneID, t.PhoneName, t.Active, t.Status, q.[Quantity]
FROM Phones as t
inner join
(
select PhoneID, COUNT(PhoneID) as [Quantity]
from Phones
group by PhoneID
) as q
on q.[PhoneID] = t.[PhoneID]
WHERE t.Status = 1

您需要关联子查询，尝试:

SELECT ID, PhoneID, PhoneName, Active, Status,
(SELECT Count(*) FROM Phones p2 WHERE p2.PhoneId = p.PhoneId) Quantity
FROM Phones p
WHERE Status = 1;

SELECT Count(PhoneID) FROM Phones没有WHERE子句来限制它的状态。