I'm writing a report to find inventory items with negative quantity available for sale based on back orders, sales orders, purchase orders, etc. In this report there is a field for Primary Vendor and Lead Time (for purchasing). Some item numbers have multiple rows in the database because they have multiple vendors. Since this table has each availble vendor it also contains the lead time field. There is another table that identifies the primary vendor for each item. In this table there is only one row per item number but there is no lead time.