Question

Is there a way to query different databases based on the value of a column in the query?

Say for example you have the following columns:

• id
• part_id
• attr_id
• attr_value_ext
• attr_value_int

You then run a query and if the attr_id is ‘1’ is returns the attr_value_int column but if attr_id is greater than ‘1’ it joins data from another table based on the attr_value_ext.

Answer 1

something like this?

select case when a.id = 1 then a.attr_value_int
            when a.id > 1 then b.some_other_col
            else null end as whatever
from first_table a
     left outer join other_table b
     on ( a.attr_val_ext = b.id )
/