Sql 在ORACLE中查找上一季度的第一天和最后一天

我对表格有一个疑问：

select *
from X
where <some_date is in the last quarter>

我真的很难找到上个季度的正确日期。所以，假设当前日期是7月1日，即第三季度，我希望将4月1日作为第一季度，将6月30日作为最后一季度（即第二季度）的最后一天

谷歌搜索了一下，发现了大量的解决方案，但每一个都涵盖了SQL Server和我们的ORACLE数据库ORACLE 10g和11g上没有的时髦方法

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哦，是的，而且我还需要能够将整个内容放到一个查询中，因为这是某个工具对我施加的限制，该工具将进一步处理此查询…：/

典型的情况是，我一请求帮助，就会找到一些博客，让我知道如何继续

设法拼凑出一些说法，但绝对是丑陋的

select
    TRUNC(ADD_MONTHS(sysdate, -3),'Q') as first,
    LAST_DAY(TRUNC(ADD_MONTHS(sysdate, -3),'Q')+ 85) as last
from dual;

这似乎很管用，但是如果有人知道更好的解决方案，请告诉我！截止日期“2011年1月27日”是其中的一个示例日期

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编辑：修正了一个错误-在一个季度的第一天增加3个月并不总是在同一个季度结束。现在更难看了，该死的公历

这是一种方法，它省去了计算第一个和最后一个日期的麻烦，并将结果放入主查询的where子句中：

select
    *,
    round(to_number(to_char(some_date, 'mm')) / 4) as quarter
from x
where round(to_number(to_char(some_date, 'mm')) / 4) = round(to_number(to_char(sysdate, 'mm')) / 4)

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这是一个更简单的方法，但可能仍然不是最简单的方法：

SELECT
  ADD_MONTHS(TRUNC(SYSDATE, 'Q'), -3) AS First,
  TRUNC(SYSDATE, 'Q') - 1 AS Last
FROM DUAL

也许您还可以使用如下子选择来排除某些代码重复：

SELECT
  ADD_MONTHS(D, -3) AS First,
  D - 1 AS Last
FROM (SELECT TRUNC(SYSDATE, 'Q') AS D FROM DUAL)

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我知道这个话题很古老，也很封闭，但这就是我正确解决这个问题的方式

SELECT TRUNC(to_date('05.06.2020', 'dd.mm.yyyy'), 'Q') f_date,
      LAST_DAY(ADD_MONTHS(TRUNC(TO_DATE('05.06.2020', 'dd.mm.yyyy'), 'Q'),2) ) l_date
 FROM dual;

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请编辑您的帖子，以便对代码进行格式化。非常感谢。

SELECT DATE_CURRENT
     , TRUNC (ADD_MONTHS (DATE_CURRENT, -6), 'Q')                  AS FIRST
     , LAST_DAY (TRUNC (ADD_MONTHS (DATE_CURRENT, -6), 'Q') + 85)  AS LAST
     , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-1))                  AS PREVIOUS_QUARTER_END
     , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-1)),-3)+1 AS PREVIOUS_QUARTER_START
FROM
       (
             SELECT TO_DATE ('31.07.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
       UNION SELECT TO_DATE ('30.06.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
       UNION SELECT TO_DATE ('30.04.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
       UNION SELECT TO_DATE ('31.03.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
       )
order by DATUM;

SELECT
  TRUNC(SYSDATE, 'Q')AS FIRST_DAY,
  last_day(add_months(TRUNC(SYSDATE, 'Q'),2)) as LAST_DAY                
FROM DUAL;

    SELECT DATE_CURRENT
         , TRUNC (DATE_CURRENT, 'Q')                  AS Q1F
         , LAST_DAY (ADD_MONTHS(TRUNC (DATE_CURRENT, 'Q'),2))  AS Q1L
         , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-1))                  AS Q2F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-1)),-3)+1 AS Q2L
              , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-4))                  AS Q3F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-4)),-3)+1 AS Q3L
                   , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-7))                  AS Q4F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-7)),-3)+1 AS Q4L
                        , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-10))                  AS Q5F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-10)),-3)+1 AS Q5L
                        , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-13))                  AS Q6F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-13)),-3)+1 AS Q6L
                           , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-16))                  AS Q7F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-16)),-3)+1 AS Q7L
                     , LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-19))                  AS Q8F
         , ADD_MONTHS(LAST_DAY (ADD_MONTHS(trunc(DATE_CURRENT,'Q'),-19)),-3)+1 AS Q8L
    FROM
           (
                 SELECT TO_DATE ('05.03.2017', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
           UNION SELECT TO_DATE ('30.06.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
           UNION SELECT TO_DATE ('30.04.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
           UNION SELECT TO_DATE ('31.03.2014', 'DD.MM.YYYY') AS DATE_CURRENT FROM DUAL
           )

SELECT TRUNC(to_date('05.06.2020', 'dd.mm.yyyy'), 'Q') f_date,
      LAST_DAY(ADD_MONTHS(TRUNC(TO_DATE('05.06.2020', 'dd.mm.yyyy'), 'Q'),2) ) l_date
 FROM dual;