SQL GROUP BY有條件嗎？

Question

我試圖將名爲「CLOUD」的表複製到名爲「t1_temp」的新表中，同時基於名爲「tag」的列對行進行分組。但我希望只有在「NeighborhoodID」列相同時纔會發生這種情況。

我運行查詢：

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：

第三個條目不應與1號&第4項的分組，因爲「NeighborhoodID」 ISN」同樣的。

我希望我很清楚，如果不是請評論，謝謝。

Answer 1

您可以通過多個列組，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

我猜你的意思是還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 

這是否幫助添加NeighborhoodID到組？