[O] How to join cells in tables and center content

[Ivanov Dmitry]

Suppose, I am writing a database table structure.
Is it possible to join the 1-st two cells? And make 'table1' centered?
Current view and desired:


| table1 |       |          |     table1     |
|--------+-------+          |--------+-------+
| id     | value |    ->    | id     | value |
|        |       |          |        |       |


I understand, that it will require programming. Just give me a hint, where is 
the function, expanding table cells, and I'll try to implement it.