MySQL的 - 行分列並保持空

Question

我們有如下表（測試2）在MySQL數據庫（MySQL的5.6）：

TEAM_ID,MEMBER_ID,TYPE,SCORE 
1,2,A,150 
1,3,B,200 
1,1,B,50 
1,1,A,100 
1,2,B,NULL 

我們試着變換/旋轉基於該類型的列上表：

如果TYPE列的值爲== A，則將SCORE列中的值移動到名爲A_SCORE的新列中。如果SCORE列中的值爲NULL，則應在新的A_SCORE列中顯示NULL。

如果TYPE列的值爲== B，則將SCORE列中的值移動到名爲B_SCORE的新列中。如果SCORE列中的值爲NULL，則應在新的B_SCORE列中顯示NULL。

下表是我們正在尋找的（想要的表）的一個：我們嘗試下面的查詢

SELECT TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,SUM(A_SCORE-B_SCORE) AS ACTUAL_MINUS_B_SCORE FROM 
    (SELECT TEAM_ID,MEMBER_ID, 

CASE 
WHEN SCORE IS NULL 
THEN NULL 
ELSE SUM(if(TYPE = 'A', SCORE,0)) 
END A_SCORE, 

CASE 
WHEN SCORE IS NULL 
THEN NULL 
ELSE SUM(if(TYPE = 'B', SCORE,0)) 
END B_SCORE 
FROM TEST2 
GROUP BY TEAM_ID,MEMBER_ID,SCORE) AS A 
GROUP BY TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE); 

TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,A_SCORE_MINUS_B_SCORE 
1,1,100,50,50 
1,2,150,NULL,NULL 
1,3,0,200,-200 

它返回的東西我們不想：

TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,A_SCORE_MINUS_B_SCORE 
1,1,0,50,-50 
1,1,100,0,100 
1,2,0,0,0 
1,2,150,0,150 
1,3,0,200,-200 

如果我們嘗試以下操作，它會生成一個與我們想要的相近的表，但它不會返回n任何NULL值。

SELECT TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,SUM(A_SCORE-B_SCORE) AS A_SCORE _MINUS_B_SCORE FROM 
    (SELECT TEAM_ID,MEMBER_ID, 

SUM(if(TYPE = 'A', SCORE,0)) AS A_SCORE, 

SUM(if(TYPE = 'B', SCORE,0))AS B_SCORE 
FROM TEST2 
GROUP BY TEAM_ID,MEMBER_ID) AS A 
GROUP BY TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE; 

上述查詢的結果：

TEAM_ID,MEMBER_ID,A_SCORE,B_SCORE,A_SCORE_MINUS_B_SCORE 
1,1,100,50,50 
1,2,150,0,0 
1,3,0,200,-200 

可以在任何大師指教如何生成在這種情況下使用MySQL想要的表？ SQL小提琴在這裏是爲了您的方便。

http://sqlfiddle.com/#!9/cfe7a1/1

謝謝！

Answer 1

試試這個;）

SELECT TEAM_ID, MEMBER_ID, A_SCORE, B_SCORE, A_SCORE - B_SCORE AS A_SCORE_MINUS_B_SCORE 
FROM (
    SELECT 
     TEAM_ID, MEMBER_ID, 
     CASE 
      WHEN A_SCORE IS NULL AND NOT EXISTS (
       SELECT 1 FROM TEST2 
       WHERE TEAM_ID = T1.TEAM_ID 
       AND MEMBER_ID = T1.MEMBER_ID 
       AND TYPE = 'A' 
      ) THEN 0 ELSE A_SCORE END AS A_SCORE, 
     CASE 
      WHEN B_SCORE IS NULL AND NOT EXISTS (
       SELECT 1 FROM TEST2 
       WHERE TEAM_ID = T1.TEAM_ID 
       AND MEMBER_ID = T1.MEMBER_ID 
       AND TYPE = 'A' 
      ) THEN 0 ELSE B_SCORE END AS B_SCORE 
    FROM (
     SELECT 
      TEAM_ID, MEMBER_ID, 
      MAX(CASE WHEN TYPE = 'A' THEN SCORE END) AS A_SCORE, 
      MAX(CASE WHEN TYPE = 'B' THEN SCORE END) AS B_SCORE 
     FROM TEST2 
     GROUP BY TEAM_ID, MEMBER_ID 
    ) T1 
)T 

SQLFiddle demo here

Answer 2

我不太明白的計算標準，但這樣的事情應該工作...

SELECT team_id 
    , member_id 
    , COALESCE(MAX(CASE WHEN type = 'A' THEN score END),0) a_score 
    , COALESCE(MAX(CASE WHEN type = 'B' THEN score END),0) b_score 
    , COALESCE(MAX(CASE WHEN type = 'A' THEN score END),0) 
    - COALESCE(MAX(CASE WHEN type = 'B' THEN score END),0) diff 
    FROM test2 
GROUP 
    BY team_id 
    , member_id;