从两个表中读取数据

Question

考虑下面列出的表格

Table credit

id    cr_amount  created_date

1     1000       2011-07-01
2     2000       2011-07-08
3     6000       2011-07-09

Table debit 个条目如下。

id   dr_amount  created_date

1    3000       2011-07-09

需要按照 created date 的顺序从上面的表格中读取列 cr_amount、dr_amount 和 created_date，如下所示。

cr_amount  dr_amount   created_date

1000        NULL         2011-07-01
2000        NULL         2011-07-08
6000        NULL         2011-07-22
NULL        3000         2011-07-09

Answer 1

您可能需要将两列都放入 union all:

select cr_amount,Null as 'db_amount',created from table_credit
union all
select Null,db_amount,created from table_debit
order by created