David G Johnston wrote
>
> CrashBandi wrote
>> Hi,
>>
>> I am having the following question. I am not sure how to approach it.
>> Please help!
>>
>> table A
>> name col1 col2 col3 col4 apple 100 11111 1 APL orange 200 22222 3 ORG
>> carrot 300 33333 3 CRT
>>
>> table B
>> custom_name value obj_type obj_id apple a FR 100 orange o FR 200
>> carrot
>> c VG 300 apple d FR 11111 orange e VG 22222 carrot f UC 33333 apple h
>> VG
>> 1 orange o FR 3 carrot c VG 3
>> when obj_type ='FR' then join on col1
>> When obj_type='VG' then join on col2
>> When obj_type='UC' then join on col2
>>
>> Thanks In advance,
>> CB
> You cannot do conditional joins in this manner. You will need to write
> three joins, one each against a subquery with the appropriate where
> clause.
>
> David J.
Actually you might be able to do:
On (case obj_type when 'xxx' then col1 when 'yyy' then col2 end = obj_id)
But I haven't tried something like this before.
David J.
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