oracle数据库:
https://www.cnblogs.com/summary-2017/p/7263220.html
Oracle 数据库比较日期大小
select * from JN_BUS_KJLWSBJBXX where dqsj <= to_date('2007-09-07 00:00:00','yyyy-mm-dd hh24:mi:ss')
查某月的入职:
select count(1) from databasename.tablename where to_char(indate,'YYYY/MM') = '2019/07'