Oracle 按年、月排序答案

【问题标题】：Oracle order by year, monthOracle 按年、月排序
【发布时间】：2014-04-10 09:52:56
【问题描述】：

我有一个查询，我想按年订购，然后按月订购。我尝试按 to_date(depdate, 'mm') 和 TO_CHAR(depdate, 'YYYY/MM') 排序。这是我正在查询的表和查询本身的 sqlfiddle sqlfiddle

【问题讨论】：

为什么小提琴是空的？

【解决方案1】：

您希望按date 值排序，而不是按字符串表示。这意味着您还想要group by date 值。 trunc(<<date column>>, 'mm') 将 date 截断到每月第一天的午夜。所以像这样的

SELECT to_char(trunc(DEPDATE,'MM'), 'Mon-YYYY') AS MONTH, 
       SUM(AMOUNTROOM) AS ROOMTOTAL, 
       SUM(AMOUNTEXTRAS) AS EXTRATOTAL, 
       SUM(AMOUNTEXTRAS + AMOUNTROOM) AS OATOTAL 
FROM checkins 
WHERE checkinstatus = 'D' AND depdate > TO_DATE('2013-12-01', 'yyyy/mm/dd') 
  AND depdate <= TO_DATE('2014-04-10', 'yyyy/mm/dd')
GROUP BY trunc(depdate,'mm')
ORDER BY trunc(depdate,'mm');

应该是你要找的。见the updated fiddle

【讨论】：

【解决方案2】：

查看此查询。如果它是一个日期字段，只需简单的 order by 就可以了。您无需使用 TO_CHAR 转换为字符串然后排序：

WITH TAB AS
(
 SELECT SYSDATE  DATEVAL FROM DUAL
 UNION
 SELECT SYSDATE + 100 DATEVAL FROM DUAL
 UNION
 SELECT SYSDATE -500 DATEVAL FROM DUAL
 UNION
 SELECT SYSDATE + 30 DATEVAL FROM DUAL
 UNION
 SELECT SYSDATE -30 DATEVAL FROM DUAL
) SELECT * FROM TAB
ORDER BY DATEVAL DESC

【讨论】：

SELECT to_char(DEPDATE,'Mon-yyyy') AS MONTH, SUM(AMOUNTROOM) AS ROOMTOTAL, SUM(AMOUNTEXTRAS) AS EXTRATOTAL, SUM(AMOUNTEXTRAS + AMOUNTROOM) AS OATOTAL FROM checkins WHERE checkinstatus = ' D' AND depdate > TO_DATE('2013-12-01', 'yyyy/mm/dd') AND depdate