连接两个表并合并mysql中的公共列

Question

I have 2 mysql tables:

t1 with columns as follows:
customer, datetime, products1
t2 with columns as follows:
customer, datetime, products2
t1: customer  datetime             products1  country
    111       2018-11-23 01:12:33    p1         A
    111       2018-11-23 01:13:00    p2         A   
    112       2018-11-23 01:12:12    p1         B
    112       2018-11-23 01:15:10    p3         B


t2: customer  datetime             products2
    111       2018-11-23 01:12:40    q1
    111       2018-11-23 01:13:00    q2
    112       2018-11-23 01:12:10    q1
    112       2018-11-23 01:15:20    q3

I would like to join both as doing and outer join with mysql and get only 1 datetime, 1 customer and merge both products and finally order by datetime. So I want something like this:

 customer         datetime              products    country
  112             2018-11-23 01:12:10     q1          NULL
  112             2018-11-23 01:12:12     p1          B
  111             2018-11-23 01:12:33     p1          A
  111             2018-11-23 01:12:40     q1          NULL
  111             2018-11-23 01:13:00     p2          A
  111             2018-11-23 01:13:00     q2          NULL
  112             2018-11-23 01:15:10     p3          B
  111             2018-11-23 01:13:00     q2          NULL

I am just wondering about how to merge the two datetimes into only one and same for products.

Answer 1

Since there's no common data between the two tables, I think you want a UNION , not a MERGE . Try this:

SELECT
  customer,
  datetime,
  products1 as products,
  country
FROM t1
UNION
SELECT
  customer,
  datetime,
  products2 as products,
  null as country
FROM t2