Question

我有这样的数据库结构：

Table - lodges
LodgeID (PK)
Lodge
etc

Table - scores
ScoreID (PK)
Score
CategoryID
LodgeID (FK)

我试图以以下形式返回结果：

LodgeID，Lodge，Category，该类别中的得分数，该类别中的平均得分

例如，如果我有：

小屋

LodgeID, Lodge
1, Lodge One
2, Lodge Two

分数

ScoreID, Score, CategoryID, LodgeID
1, 3, 101, 1
2, 5, 101, 1
3, 7, 101, 1
4, 10, 102, 2
5, 20, 102, 2
6, 30, 102, 2
7, 40, 102, 2

我想回来：

1, Lodge One, 3, 5
2, Lodge Two, 4, 25

我一直在尝试这样的事情：

SELECT        COUNT(ScoreID) as scoreCount, AVG(Score) as AverageScore, Lodge 
FROM          scores_temp 
INNER JOIN    lodges_temp ON scores_temp.LodgeID = lodges_temp.LodgeID

SELECT lodges_temp.LodgeID，Lodge，COUNT（ScoreID）为scoreCount，AVG（Score）为AverageScore FROM lodges_temp INNER JOIN scores_temp ON lodges_temp.LodgeID = scores_temp.LodgeID

没有任何成功。任何指针都会非常感激。

Answer 1

试试这个

SELECT        COUNT(ScoreID) as scoreCount, AVG(Score) as AverageScore, Lodge 
FROM          scores_temp 
INNER JOIN    lodges_temp ON scores_temp.LodgeID = lodges_temp.LodgeID
GROUP BY Lodge

Answer 2

您缺少group by条款：

SELECT     COUNT(ScoreID) as scoreCount, AVG(Score) as AverageScore, Lodge 
FROM       scores
INNER JOIN lodges ON scores.LodgeID = lodges.LodgeID
GROUP BY   lodge

SQL查询 - 使用COUNT

2 个答案: