Oracle获取月初/月末/季初/季末/半年初/半年末/年初/年末

      V_BEGIN_DT_M DATE;  --按月开始日期
      V_BEGIN_DT_Q DATE;  --按季开始日期
      V_BEGIN_DT_H DATE;  --按半年开始日期
      V_BEGIN_DT_Y DATE;  --按年开始日期
      V_END_DT_M DATE;  --按月结束日期
      V_END_DT_Q DATE;  --按季结束日期
      V_END_DT_H DATE;  --按半年结束日期
      V_END_DT_Y DATE;  --按年结束日期

           SELECT 
              TRUNC(V_DATE,'MM') V_DATE_M,--月报
              TRUNC(V_DATE,'Q') V_DATE_Q, --季报
              CASE
                WHEN TO_CHAR(V_DATE,'MM') <'07' THEN TRUNC(V_DATE,'YYYY')
                WHEN TO_CHAR(V_DATE,'MM') >'06' THEN PKG_COMM_UTIL.FUNC_TO_DATE((TO_CHAR(V_DATE,'YYYY') || '0701'),'YYYYMMDD')
              END V_DATE_H,                 --半年报
              TRUNC(V_DATE,'YYYY') V_DATE_Y, --年报
              LAST_DAY(V_DATE) AS V_END_DT_M, 
              ADD_MONTHS(TRUNC(V_DATE,'Q'),3)-1 AS V_END_DT_Q,
              CASE
                WHEN TO_CHAR(V_DATE, 'MM') < '07' THEN ADD_MONTHS(TRUNC(V_DATE,'YYYY'),6)-1
                WHEN TO_CHAR(V_DATE, 'MM') > '06' THEN ADD_MONTHS(TRUNC(V_DATE,'YYYY'),12)-1
              END AS V_END_DT_H,
              ADD_MONTHS(TRUNC(V_DATE,'YYYY'),12)-1 AS V_END_DT_Y
          INTO V_BEGIN_DT_M, V_BEGIN_DT_Q, V_BEGIN_DT_H, V_BEGIN_DT_Y,
               V_END_DT_M, V_END_DT_Q, V_END_DT_H, V_END_DT_Y   
          FROM DUAL;