如何将 3 个表的组合插入具有 3 个对应列的第 4 个表中？

Question

I have the following tables:

 table1:       table2:       table3:  

|  id  |      |  id  |      |  id  |
|------|      |------|      |------|    
|  1   |      |  1   |      |  1   |
|  2   |      |  2   |      |  2   |

How can I execute a MySql Query which inserts into a 4th table (table4) all possible combinations of the above tables which has according columns (id1, id2, id3)?

Basically I want my table4 to look like this:

| id1 | id2 | id3 |
|-----|-----|-----|
|  1  |  1  |  1  |
|  1  |  1  |  2  |
|  1  |  2  |  1  |
|  1  |  2  |  2  |
|  2  |  1  |  1  |
|  2  |  1  |  2  |
|  2  |  2  |  1  |
|  2  |  2  |  2  |

Answer 1

You would use create table as and cross join :

create table table4 as
    select t1.id as id1, t2.id as id2, t3.id as id3
    from table1 t1 cross join
         table2 t2 cross join
         table3 t3;

Note that SQL tables represent unordered sets. So, if you want to see the results in the order you have specified, then use:

select t4.*
from table4 t4
order by id1, id2, id3;