pl/sql如其查询上月记录

pl/sql如果查询上月记录
如题

------解决方案--------------------
select to_char(trunc(sysdate, 'MM ') - 1, 'YYYY-MM-dd ') || ' 23:59:59 ' as firstdt from dual
select to_char(trunc(sysdate, 'MM ') - 1, 'YYYY-MM ') || '-01 00:00:00 ' as lastdt from dual
------解决方案--------------------
啊，写反了
select to_char(trunc(sysdate, 'MM ') - 1, 'YYYY-MM-dd ') || ' 23:59:59 ' as lastdt from dual
select to_char(trunc(sysdate, 'MM ') - 1, 'YYYY-MM ') || '-01 00:00:00 ' as firstdt from dual