MySQL返回联合选择结果分组

Question

I would like to know if is possible to return the results from UNION grouped by their alias. For instance:

(SELECT * FROM table1) AS first
UNION
(SELECT * FROM table2) AS second

so that the result is:

first = contains all table1 rows
second = contains all table2 rows

Practically i want an associative array like this:

[]=>[
    'first'=>[table1 results],
    'second'=>[table2 results]
]

I tried it but doesn't work. Maybe i'm doing it bad. Can this be done with a single query or i've to do 2 separated queries. Thanks.

Answer 1

You cannot do this with union because it removes duplicates. You can with union all .

One way is:

SELECT t.*, 0 as which FROM table1 t
UNION ALL
SELECT t.*, 1 FROM table2 t
ORDER BY which;

If you don't want to see which in the output, use a subquery:

select . . .
from (select t.*, 0 as which from table1 t union all
      select t.*, 1 as which from table1 t
     ) t
order by which;