通過查詢和連接訪問（sql）組

Question

我有兩個數據表，

 Project (ID, NAME, price),
 Expenses (ID, NAME, price, PROJECT_ID,)

我想找到所有帶有項目費用摘要的項目我試過這個查詢，但我無法得到所有項目，只有他有的費用

SELECT PROJECT.p_id, SUM(EXDE.EXD_AMOUNT) AS T
FROM  PROJECT 
INNER JOIN EXDE
    ON PROJECT.p_id = EXDE.P_NO
GROUP BY  PROJECT.p_id

我非常感謝任何答案都能幫助我找到解決方案

Answer 1

內部聯接僅選擇兩個表中的匹配項。 你需要左加入。

SELECT PROJECT.p_id, SUM(EXDE.EXD_AMOUNT) AS T
FROM  PROJECT 
LEFT JOIN EXDE
    ON PROJECT.p_id = EXDE.P_NO
GROUP BY  PROJECT.p_id

Answer 2

請改用LEFT JOIN 。

SELECT   PROJECT.p_id, SUM(EXDE.EXD_AMOUNT) AS T
  FROM   PROJECT 
             LEFT JOIN EXDE
               ON PROJECT.p_id = EXDE.P_NO
GROUP BY  PROJECT.p_id