SQL GROUP BY有条件吗？

Question

我试图将名为“CLOUD”的表复制到名为“t1_temp”的新表中，同时基于名为“tag”的列对行进行分组。但我希望只有在“NeighborhoodID”列相同时才会发生这种情况。

我运行查询：

INSERT INTO t1_temp (id, NeighborhoodID, power, tag) 
     SELECT id, NeighborhoodID, SUM(power), tag 
     FROM CLOUD GROUP BY tag ORDER BY NeighborhoodID 

因此，例如：

第三个条目不应与1号&第4项的分组，因为“NeighborhoodID” ISN”同样的。

我希望我很清楚，如果不是请评论，谢谢。

Answer 1

您可以通过多个列组，所以：

INSERT INTO t1_temp (id, NeighborhoodID, power, tag) 
    SELECT id, NeighborhoodID, SUM(power), tag 
    FROM CLOUD GROUP BY tag, NeighborhoodID ORDER BY NeighborhoodID 

Answer 2

我猜你的意思是还by子句

SELECT id, NeighborhoodID, SUM(power), tag 
    FROM CLOUD 
    GROUP BY tag, NeighborhoodID 
    ORDER BY NeighborhoodID 

Answer 3

INSERT INTO t1_temp (id, NeighborhoodID, power, tag) 
SELECT min(id), NeighborhoodID, SUM(power), tag 
FROM CLOUD 
GROUP BY NeighborhoodID, tag ORDER BY NeighborhoodID 

这是否帮助添加NeighborhoodID到组？