mysql IF or CASE help

[chucklarge]

Hello

I am trying to figure out if i can use the mysql control structures in this way.

-Primary-
+-----+----+
| id | name |
+-----+----+
| 1 | Dave |
| 2 | Jason |
| 3 | Jeff |
| 6 | Jeremy |
| 9 | Sam |
+-----+----+

-Shipping-
+-----+----+
| id | name |
+-----+----+
| 1 | Martin|
| 2 | Andrew |
| 3 | Dana |
| 4 | Chris |
| 5 | John |
+-----+----+

-Relation-
+-----+----+------+
| id | type | ps_id |
+-----+----+------+
| 1 | Shipping| 3 |
| 2 | Shipping| 5 |
| 3 | Primary | 9 |
| 4 | Shipping| 1 |
| 5 | Primary | 1 |
+-----+----+------+

Bascially I have two tables with the same fields. I have a 3rd table that that tells me the table and id to select. Right Now, I am doing this with php, but need to find a way to do this with a mysql statement. Can anyone help me with the the control flow statement that will produce the following output ?

Dana
John
Sam
Martin
Dave

Thanks,
Chuck

[DaemonProjects]

Select both tables in a statement

SELECT Primary., Shipping. FROM Primary, Shipping;

[chucklarge]

Thanks DaemonProjects, but what i want is to return the correct results based on the relations table. The 'type' field dictates which table to return results from in that line.

[mjax]

I don't think this can be done in a SQL query and to be honest, this kind of construction reeks like a case of bad database design.

[Roger_Ramjet]

It could be done with a UNION query, the two selects each operating on a different table with the correct where conditions.

I agree with mjax, bad design in the first place.