Question

CLOSE_DATE字段IS NOT NULL：

时，以下选项有效

SELECT
    YEAR (CLOSE_DATE) AS TheYear,
    MONTH (CLOSE_DATE) AS TheMonth,
    COUNT (*) AS cnt
FROM
    Table1
WHERE
    Table1.DEPT = 'SUPPORT'
GROUP BY
    YEAR (CLOSE_DATE),
    MONTH (CLOSE_DATE)
ORDER BY
    TheYear DESC,
    TheMonth DESC

输出结果为：

+-------------+------+
| Year | Month | cnt |
+-------------+------+
| 2014 |     4 |  10 |
| 2014 |     3 |   9 |
| 2014 |     2 |  15 |
| 2014 |     1 |  12 |
| 2013 |    12 |  10 |
| 2013 |    11 |  50 |
+--------------+-----+

如果CLOSE_DATE有7行NULL，则结果为：

+-------------+------+
| Year | Month | cnt |
+-------------+------+
| NULL |  NULL |   7 |
| 2014 |     4 |  10 |
| 2014 |     3 |   9 |
| 2014 |     2 |  15 |
| 2014 |     1 |  12 |
| 2013 |    12 |  10 |
| 2013 |    11 |  50 |
+--------------+-----+

NULL表示它应该计入实际年份和月份，因此预期结果应为：

+-------------+------+
| Year | Month | cnt |
+-------------+------+
| 2014 |     4 |  17 |
| 2014 |     3 |   9 |
| 2014 |     2 |  15 |
| 2014 |     1 |  12 |
| 2013 |    12 |  10 |
| 2013 |    11 |  50 |
+--------------+-----+

更新

上面的例子只是更大选择的一部分。我实际上是为了打开和关闭案件。

如果故障单没有close_date，则表示它已打开。因此，如果计算得很接近它应该算作开放。

选择相同，打开列：

SELECT
    YEAR (OPEN_DATE) AS TheYear,
    MONTH (OPEN_DATE) AS TheMonth,
    COUNT (*) AS cnt
FROM
    Table1
WHERE
    Table1.DEPT = 'SUPPORT'
GROUP BY
    YEAR (OPEN_DATE),
    MONTH (OPEN_DATE)
ORDER BY
    TheYear DESC,
    TheMonth DESC

因此，行YEAR (OPEN_DATE) AS TheYear,和MONTH (OPEN_DATE) AS TheMonth,会带来open_date列中的年份和月份，但是如果close_date列is null它应该依赖那条线也是。

这样，close_date中包含空值的所有行都将被视为open_date。

Answer 1

您可以使用Isnull()函数，只要null值出现，此函数就会允许另一个预定义值。

SELECT
    YEAR (Isnull(CLOSE_DATE,getdate())) AS TheYear,
    MONTH (Isnull(CLOSE_DATE,getdate())) AS TheMonth,
    COUNT (*) AS cnt
FROM
    Table1
WHERE
    Table1.DEPT = 'SUPPORT'
GROUP BY
    YEAR (Isnull(CLOSE_DATE,getdate())),
    MONTH (Isnull(CLOSE_DATE,getdate()))
ORDER BY
    TheYear DESC,
    TheMonth DESC

选择计数＆＃34; Null＆＃34;和＆＃34;不是空的＆＃34;

1 个答案: