如何分月份查询出1-12个月的语句

Question

查询出  1 - 12 月份的 数据SQL例如A表：
field1               field2  
20170201      20180201
20160316      20160528
20160929      20160222
20160201      20160414
20180209      20170801
        .                        .
        .                        .
        .                        .

Answer 1

select to_char(add_months(sysdate, -level + 1), 'yyyymm') mm from dual
connect by level <= 12
;