我在日期型別的表中有兩列（比如 Permissioned_on_Ques1、Permissioned_on_Ques2）。我想在兩列的最新更新日期對表格進行排序。如果兩個日期相等，它應該選擇第一列。
Permissioned_on_Ques1 Permissioned_on_Ques2
31 Mar 2022 04:17:33 31 Mar 2022 04:17:33
30 Mar 2022 06:25:09 25 Feb 2022 03:35:43
uj5u.com熱心網友回復：
您可以使用greatest函式查找兩個日期中較大的一個并將其用于order by：
order by greatest(Permissioned_on_Ques1, Permissioned_on_Ques2) desc
uj5u.com熱心網友回復：
嘗試：
SELECT
Permissioned_onQues1,
Permissioned_onQues2
FROM
yourTableName
ORDER BY
CASE WHEN Permissioned_onQues1 = Permissioned_onQues2
THEN Permissioned_onQues1
ELSE Permissioned_onQues2
END
DESC
uj5u.com熱心網友回復：
如果 Permissioned_on_Ques1 和 Permissioned_on_Ques2 不是空列：
SELECT *
FROM <table>
ORDER BY GREATEST ( Permissioned_on_Ques1
, Permissioned_on_Ques2
) desc
如果列可以有空值：
SELECT *
FROM <table>
ORDER BY CASE
WHEN Permissioned_on_Ques1 IS NOT NULL
and Permissioned_on_Ques2 IS NOT NULL
THEN GREATEST
( Permissioned_on_Ques1
, Permissioned_on_Ques2
)
ELSE COALESCE
( Permissioned_on_Ques1
, Permissioned_on_Ques2
)
END desc
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標籤：sql PostgreSQL 排序