Here is the SQL Select that I found works. I am not 100% sure it is the correct one but it has no NULL and returns the query. Here is this SQL select:

select equipment.equip_id, equipment.equip_desc, trandetail.* from trandetail  
 left join orders on orders.order_no = trandetail.order_no and trandetail.order_no > 0 and LEN(ordersequip_id) > 0
 join equipment on (trandetail.equip_pk > 0 and equipment.equip_pk = trandetail.equip_pk) or 
 (trandetail.order_no > 0 and equipment.equip_id = orders.equip_id) 

The key is that I have JOIN EQUIPMENT only once and have it with an OR. If you see anything I am doing wrong, please let me know.
Thank you.



>I would at first not try for a single select, but to get the result set right and then (perhaps) try to streamline the SQL.
>Did not try to think your text through too much, but the main problem seems to be uncertain join criteria.
>So I'd first identify both sets needing different join criteria, do each join and then union them.
>
>Still hazy if the order needs to be checked if trandetail already has a direct join...
>
>
>>I need to create a SQL Select that would return the following query:
>>

>>EQUIPMENT.EQUIP_ID, EQUIPMENT.EQUIP_DESC, TRANDETAIL.* FROM TRANDETAIL --- JOINS
>>

>>Structure of tables (simplified):
>>

>>TRANDETAIL      EQUIP_PK
>>                            ORDER_NO
>>
>>ORDERS            ORDER_NO
>>                           EQUIP_ID
>>
>>EQUIPMENT     EQUIP_ID   Char(15)  - Unique field
>>                          EQUIP_PK
>>                          EQUIP_DESC Char(40) - Equipment descriptoin
>>

>>
>>The challenge is that the SQL Select should select All Records from TRANDETAIL and records
>>from EQUIPMENT either by the field TRANDETAIL.EQUIP_PK Jointed with EQUIPMENT.EQUIP_PK
>>or by Joining ORDERS on ORDER_NO and then Joining EQUIPMENT on EQUIPMENT.EQUIP_ID with ORDERS_EQUIP_ID.
>>Therefore, it looks like I will have the table EQUIPMENT twice and this creates many NULL values.
>>
>>Is my explanation too confusing? Any suggestions?