我試圖獲取兩列之間的日期差異,然後最終得到由承包商字段分組的平均天數。我能夠獲得大部分的SQL,但我似乎無法弄清楚如何獲取多個場景的日期差異。MySQL多個if語句的日期
基本上,如果原始日期列爲空,並且新日期列不是,則獲取訂購的新日期和日期之間的日期差異。反之亦然。如果原始日期和新日期都爲空,只需將日期差異設置爲空。它應該如下所示,不考慮分組的平均天數。
SQL以下(不包括AVG函數還):
SELECT PT1.CONTRACTOR AS 'Contractor', PT1.date_order AS "date ordered", PT1.DATE_COMPLETED AS "original date", PT2.DATE_COMPLETED AS "new date",
IF(PT1.DATE_COMPLETED = NULL AND PT2.DATE_COMPLETED IS NOT NULL, DATEDIFF(PT2.DATE_COMPLETED, PT1.DATE_ORDER), IF(PT2.DATE_COMPLETED = NULL AND PT1.DATE_COMPLETED IS NOT NULL, DATEDIFF(PT1.DATE_COMPLETED, PT1.DATE_ORDER), NULL)) AS "DATE DIFF"
FROM PTABLE1 PT1
INNER JOIN PTABLE2 PT2
ON PT1.ID = PT2.ID
WHERE PT2.STATUS = 'To_do' OR PT2.STATUS = 'Completed'
AND PT2.COMPLETE = 'Yes'
-- GROUP BY PT1.CONTRACTOR
您是否考慮過使用'CASE'來獲得透明度? – BlitZ
如果你允許date diff爲0而不是null,那麼你可以使用COALESCE –
@CORRUPT爲什麼你說'NULL = NULL'會評估爲'FALSE'?它會評估爲'NULL' –