同时选择字段的最短日期和最大日期

Question

我有这个查询，它返回字段的最小日期值。

SELECT sa.ContentID, SA.MSISDN, sa.DateRegistered AS minDate, sa.DateRegistered AS maxDate 
FROM sms.dbo.SubscriptionsArchive AS sa 
INNER JOIN (SELECT MSISDN, MIN(DateRegistered) AS mindate 
      FROM sms.dbo.SubscriptionsArchive 
      GROUP BY MSISDN) mysa 
ON sa.MSISDN = mysa.MSISDN AND sa.DateRegistered = mysa.mindate 

它的输出是

但我想除了显示在同一日期的最大日期值以及到最小日期。我如何实现这一目标？

Answer 1

虽然它可能是很有诱惑力使用第二子查询联接，以获得MAX()，并再次MSISDN的最大日加入，你应该能够通过添加MAX(DateRegistered)到现有的子查询并添加OR来实现它条件在联接的ON子句中加入MSISDN,mindate或MSISDN,maxdate。

SELECT 
    sa.ContentID, 
    SA.MSISDN, 
    -- Use the join's dates by alias in the SELECT 
    mysa.mindate, 
    mysa.maxdate 
FROM 
    sms.dbo.SubscriptionsArchive AS sa 
    INNER JOIN (
    SELECT 
     MSISDN, 
     MIN(DateRegistered) AS mindate, 
     -- Add the max date 
     MAX(DateRegistered) AS maxdate, 
    FROM sms.dbo.SubscriptionsArchive 
    GROUP BY MSISDN 
) mysa 
    -- Join on either a mindate or maxdate match 
    ON (sa.MSISDN = mysa.MSISDN AND sa.DateRegistered = mysa.mindate) 
     OR (sa.MSISDN = mysa.MSISDN AND sa.DateRegistered = mysa.maxdate) 

我注意到你这个标记为mysql但dbo真的建议你使用的是MS SQL服务器。如果这是真的，那么你可以使用公用表表达式而不是子查询连接。

-- Define the subquery as a CTE instead 
WITH mysa AS (
SELECT 
    MSISDN, 
    MIN(DateRegistered) AS mindate, 
    -- Add the max date 
    MAX(DateRegistered) AS maxdate, 
    FROM sms.dbo.SubscriptionsArchive 
    GROUP BY MSISDN 
); 

SELECT 
    sa.ContentID, 
    SA.MSISDN, 
    -- Use the join's dates by alias in the SELECT 
    mysa.mindate, 
    mysa.maxdate 
FROM sms.dbo.SubscriptionsArchive AS sa 
-- Join on the CTE 
INNER JOIN mysa 
    ON (sa.MSISDN = mysa.MSISDN AND sa.DateRegistered = mysa.mindate) 
    OR (sa.MSISDN = mysa.MSISDN AND sa.DateRegistered = mysa.maxdate) 

Answer 2

您的语法建议SQL Server。如果是的话，我会建议窗口功能：

SELECT sa.ContentID, SA.MSISDN, sa.DateRegistered AS minDate, sa.DateRegistered AS maxDate 
FROM (SELECT sa.*, 
      MIN(DateRegistered) OVER (PARITION BY sa.MSISDN) as mindr, 
      MAX(DateRegistered) OVER (PARITION BY sa.MSISDN) as maxdr 
     FROM sms.dbo.SubscriptionsArchive sa 
    ) sa 
WHERE sa.DateRegistered IN (mindr, maxdr);