mysql查看另一个表中没有的数据

Question

这是我的表

 table_datetime1
2018-03-01 00:05:00
2018-03-01 00:10:00
2018-03-01 00:15:00
2018-03-01 00:20:00
2018-03-01 00:25:00

table_datetime2

2018-03-01 00:05:00
2018-03-01 00:10:00
2018-03-01 00:15:00
2018-03-01 00:20:00
2018-03-01 00:30:00

在这种情况下，2条记录不是，我想在查询中向我显示那2条记录

example
2018-03-01 00:25:00
2018-03-01 00:30:00

Answer 1

这应该给你两个记录：

select * from table1 a
left join table2 b on b.table_datetime2 = a.table_datetime1
where b.table_datetime2 is null
union
select * from table2 a
left join table1 b on b.table_datetime1 = a.table_datetime2
where b.table_datetime1 is null