oracle求上一季度的数据

Question

有一张表，本季度的数据不完整，想通过本月求上个季度的数据怎么求

Answer 1

select zzz.*
  from zzz
 where decode(to_char(sysdate, 'q'), '1', '4', '2', '1', '3', '2', '4', '3') =
       to_char(to_date(yf, 'yyyymm'), 'q')
   and decode(to_char(sysdate, 'q'),
              '1',
              to_char(sysdate, 'yyyy') - 1,
              substr(yf, 1, 4)) = substr(yf, 1, 4)

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加个开窗函数字段就好了

select zzz.*,avg(fs) over() avg_fs
  from zzz
 where decode(to_char(sysdate, 'q'), '1', '4', '2', '1', '3', '2', '4', '3') =
       to_char(to_date(yf, 'yyyymm'), 'q')
   and decode(to_char(sysdate, 'q'),
              '1',
              to_char(sysdate, 'yyyy') - 1,
              substr(yf, 1, 4)) = substr(yf, 1, 4)