选择语句 - 选择所有条目均不为空的第一组结果

Question

我正在尝试编写一个允许我选择 the latest year in which every year Value contains an entry 的选择语句

以下面的例子为例：

EarningsYearID EarningsID   Year   Value 
1                 1         2015    NULL
2                 1         2014    1.27
3                 1         2013    3.21
4                 2         2015    7.21
5                 2         2014    6.97
6                 2         2013    2.22

正确答案应该是“2014”，因为 2014 是最近一年，该年的所有条目都包含 NOT NULL 值。

我尝试了以下查询：

将@YearInWhichEarningsExistForAllComparisonCompanies 声明为 int； SET @YearInWhichEarningsExistForAllComparisonCompanies = (SELECT TOP 1 ey.[Year] 从公司 c，收益 e，收益年份 ey 在哪里 c.ticker_id = e.ticker_id AND e.EarningsID = ey.EarningsID AND c.tickerSymbol IN ('AA', 'BB') AND ey.Value 不为空 ORDER by ey.[Year] DESC);

但是，这会返回不正确的“2015”，因为存在一个为 NULL 的“2015”条目，我要求所有条目都不是 NULL。因此，下一个可用年份 2014 应该是正确的答案。

希望这是有道理的。

Answer 1

您的查询缺少按列排序，您可以尝试以下代码：

SET @YearInWhichEarningsExistForAllComparisonCompanies = (SELECT TOP 1 ey.[Year]
    FROM company c, earnings e, earningsYear ey
    WHERE c.ticker_id = e.ticker_id
    AND e.EarningsID = ey.EarningsID
    AND c.tickerSymbol IN ('AA', 'BB')
    AND ey.Value is not null ORDER by ey.EarningsID, ey.[Year] DESC);

你也可以参考下面的可读性：

SELECT TOP 1
    @YearInWhichEarningsExistForAllComparisonCompanies = ey.[Year]
FROM
    company c
    JOIN earnings e ON c.ticker_id = e.ticker_id
    JOIN earningsYear ey ON e.EarningsID = ey.EarningsID
WHERE
    c.tickerSymbol IN ('AA', 'BB')
    AND ey.Value is not null
ORDER by
    ey.EarningsID, 
    ey.[Year] DESC

请参阅下面的更新脚本：

; WITH YEARVALUE ([Year], Value)
AS
(
    SELECT
        ey.[Year], ey.Value
    FROM
        company c
        JOIN earnings e ON c.ticker_id = e.ticker_id
        JOIN earningsYear ey ON e.EarningsID = ey.EarningsID
    WHERE
        c.tickerSymbol IN ('AA', 'BB')
)

SELECT
    @YearInWhichEarningsExistForAllComparisonCompanies = MAX(Year)
FROM
    YEARVALUE
WHERE
    [Year] NOT IN (
        SELECT
            Year
        FROM
            YEARVALUE
        WHERE
            Value IS NULL)

SELECT @YearInWhichEarningsExistForAllComparisonCompanies --show latest year with no null value

Answer 2

如果值为正

select max([Year]) 
from 
(
SELECT [Year]
FROM company c, earnings e, earningsYear ey
WHERE c.ticker_id = e.ticker_id
AND e.EarningsID = ey.EarningsID
AND c.tickerSymbol IN ('AA', 'BB') 
group by [Year]
having min(isnull(ey.Value, -1000)) > -1000 
) tt