Update query to set null value lookup field

[alexjose]

I've got a web database on SharePoint to handle inventory. The table I want to update is 'Parts' and the field in that table is 'Package Type'. It is a lookup field that gets its value from another table called 'Packages'. The 'Packages' table only has 4 entries so far.

What I want to do is update all NULL values in the 'Package Type' field in 'Parts' to 'TO-46' which is in the 'Packages' field for the first entry in the 'Packages table. (See attached pictures)

Please help. Thank you!

[pbaldy]

If the tables are designed like I think,

UPDATE Parts
SET [Package Type] = 1
WHERE [Package Type] Is Null