我有一个查询做了2个左连接和1个GROUP BY，但我得到了缺少结果：

Question

以下查询应返回大约1159个结果，但只返回大约880个结果; 如果我只加入“c”宽度“mm”，我仍然可以得到1159个结果。只有当所有3个表格我得到880个结果。我也没有运气使用：RIGHT JOIN，RIGHT OUTER JOIN，LEFT OUTER JOIN，INNER JOIN。我试着用“（）”和没有“（）”的JOIN sintax也没有运气。

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SELECT c.ccod, c.cetcm, c.cdscr, c.cpcul, c.cdent, mm.amexi, 

Sum(CASE WHEN m.mcdmv=11 THEN m.mqtd END), 

Sum(CASE WHEN m.mcdmv=2 THEN m.mqtd END), 

Sum(CASE WHEN m.mcdmv=13 THEN m.mqtd END), 
Sum(CASE WHEN m.mcdmv=14 THEN m.mqtd END), 

MAX(CASE WHEN m.mcdmv=82 THEN m.mdata END) 



FROM 
(zzz.ccc c 
LEFT JOIN zzz.mmmm mm ON c.crnp = mm.arncd) 
LEFT JOIN zzz.mm m ON m.mrncd = c.crnp 



WHERE 
((c.cetcm='xcd') OR 
(c.cetcm='ewfwe') OR 
(c.cetcm='fewfew') OR 
(c.cetcm='fewf')) AND 

(m.MDATA Between 20100101 And 20110406) AND 

((m.mcdmv=11) OR 
(m.mcdmv=12) OR 
(m.mcdmv=13) OR 
(m.mcdmv=14)) AND 

(mm.aarm=1) 


GROUP BY c.ccod, c.cetcm, c.cdscr, c.cpcul, c.cdent, mm.amexi 

ORDER BY c.ccod 

Answer 1

正如有人建议，你需要移动的标准对表的左侧加入到各自的ON子句：

SELECT c.ccod, c.cetcm, c.cdscr, c.cpcul, c.cdent, mm.amexi 
    , Sum(CASE WHEN m.mcdmv=11 THEN m.mqtd END) As Total11 
    , Sum(CASE WHEN m.mcdmv=12 THEN m.mqtd END) As Total12 
    , Sum(CASE WHEN m.mcdmv=13 THEN m.mqtd END) As Total13 
    , Sum(CASE WHEN m.mcdmv=14 THEN m.mqtd END) As Total14 
    , MAX(CASE WHEN m.mcdmv=82 THEN m.mdata END) As Max82 
FROM (zzz.ccc c 
    LEFT JOIN zzz.mmmm mm 
     ON (c.crnp = mm.arncd 
     And m.aarm = 1)) 
    LEFT JOIN zzz.mm m 
     ON (m.mrncd = c.crnp 
      And m.mcdmv In(11,12,13,14,82) 
      And m.MDATA Between #20100101# And #20110406#) 
WHERE c.cetcm In('xcd','ewfwe','fewfew','fewf') 
GROUP BY c.ccod, c.cetcm, c.cdscr, c.cpcul, c.cdent, mm.amexi 
ORDER BY c.ccod 

此外，我已经使用了IN函数，它可以让你传递一系列值。顺便说一句，访问将可能会阻止列聚合函数没有列别名。在这里我只是用了一些简单的东西。