SELECT DISTINCT
report_date AS 本季度,
(
select distinct
report_date
from eva_norm_report
where
substr( report_date, 1, 4 ) = '2021'
AND to_char( to_date( report_date, 'YYYYMM' ), 'Q' ) = '1'
) as 上一季度
FROM
eva_norm_report
WHERE
substr( report_date, 1, 4 ) = '2021'
AND to_char( to_date( report_date, 'YYYYMM' ), 'Q' ) = '1'现在本季度能查出来,还有一列是查询上季度的,上季度的这个怎么做减3操作然后查出来上一季度的数据啊