因为你的关联中缺了月份列表作为尺度,可以部门先跟月份列表关联一下表MonthList Month ------ 2004-8-1 2004-9-1 2004-10-1比如查8-10月SELECT * FROM A INNER JOIN MonthList M ON M.[Month] BETWEEN '2004-8-1' AND '2004-10-1' INNER JOIN B ON B.编码 = A.编码 LEFT JOIN C ON C.编码 = A.编码 AND C.日期 = M.[Month]
Month
------
2004-8-1
2004-9-1
2004-10-1比如查8-10月SELECT *
FROM A
INNER JOIN MonthList M ON M.[Month] BETWEEN '2004-8-1' AND '2004-10-1'
INNER JOIN B ON B.编码 = A.编码
LEFT JOIN C ON C.编码 = A.编码
AND C.日期 = M.[Month]