这是比较简单的方法,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 LastFROM DUAL
也许您也可以使用子选择,例如这样,以排除某些重复代码:
SELECt ADD_MonTHS(D, -3) AS First, D - 1 AS LastFROM (SELECt TRUNC(SYSDATE, 'Q') AS D FROM DUAL)

这是比较简单的方法,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 LastFROM DUAL
也许您也可以使用子选择,例如这样,以排除某些重复代码:
SELECt ADD_MonTHS(D, -3) AS First, D - 1 AS LastFROM (SELECt TRUNC(SYSDATE, 'Q') AS D FROM DUAL)