Question

我正在开发一个拥有MS Access数据库的项目。它的结构类似于：

some id
m1(stands for month 1 jan)
m2(stands for month 2 feb)
.
.
m12( stands for month 12 dec)
year

现在要检索今年的数据我可以写

Select * from tbl where id=123 and year=2016

但我不想要一年的数据。假设它现在是七月，所以我想要从去年6月（2015年）到6月（2016年）的数据。我们怎么做？现在我在两个查询中找到结果，然后使用if else合并它。

Answer 1

这在Access 2010中似乎对我有用：

SELECT * 
FROM 
    (
        SELECT DateSerial([year], 1, 1) AS MonthStart, [m1] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 2, 1) AS MonthStart, [m2] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 3, 1) AS MonthStart, [m3] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 4, 1) AS MonthStart, [m4] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 5, 1) AS MonthStart, [m5] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 6, 1) AS MonthStart, [m6] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 7, 1) AS MonthStart, [m7] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 8, 1) AS MonthStart, [m8] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 9, 1) AS MonthStart, [m9] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 10, 1) AS MonthStart, [m10] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 11, 1) AS MonthStart, [m11] AS TheValue FROM tbl
        UNION ALL
        SELECT DateSerial([year], 12, 1) AS MonthStart, [m12] AS TheValue FROM tbl
    )
WHERE 
    MonthStart 
        BETWEEN
            DateSerial(Year(Date()) - 1, Month(Date()), 1)
        AND
            DateSerial(Year(Date()), Month(Date()) - 1, 1)
ORDER BY MonthStart

UNION ALL子查询“unpivots”数据，WHERE子句隔离前12个月的结果。

Answer 2

只需使用

Where (month in (6,7,8,9,10,11,12) and year=2015) or (month in (1,2,3,4,5,6) and year=2016) and ID=123

编辑：您可以使用

Where (month in (x to 12) and year=y) or (month in (1 to x) and year=y+1)

x是您想要的月份，y是开始年份

第二次编辑：我不知道(x to y)是否可以在访问中使用，以便您更好地使用

Where (month (Between x and 12) and year=y) or ((month Between 1 and x) and year=y+1)

当月度数据按年份列出时，如何检索前12个月的数据？

2 个答案: