If the SO--> Del is not linked to Invoice, how can we create a report with these?
What is the process which you have defined for Sales Quote--> Sales Order--> delivery?
Try to run the report by changing the table to ODLN & DLN1 instead of INV1 and OINV to confirm that you are getting valid results fordelivery.
There should be some link/ may be a udf which captures the no. of delivery or sales order so that we can create a link using query.
Thanks,
Joseph