Removing options from droplist once selected

[Luis Del Valle]

I am a United States Marine. I am creating a data base to prevent the armorers from double issuing a weapon. I have greated a drop list that looks up values (weapons serial numbers) from a weapons table. When the weapon has been selected it is saved in the main table. How do i make that particular serial number not available on the drop list, and to only show weapons that are available for issue?

[Rabbit]

As the source of the combobox, use a query that left joins to the main table and keep only the ones where it's null in the main query. That will leave only the ones that aren't in the main query.

[Luis Del Valle]

Rabbit, Thank you for taking your time to answer my question.
What do you mean by "left joins"? Can you please elaborate a little more on your answer.

[Rabbit]

SELECT someFields
FROM someTable
LEFT JOIN mainTable
ON someTable.weapon = mainTable.weapon
WHERE mainTable.weapon IS NULL

[Luis Del Valle]

I just might be stupid but I dont get it. I hope that you understand that I am a Marine and what im best at is killing the enemy of the United States. Computers, and Microsoft Access im just learning. If you can break it down for me Barney style it would be great.

[Rabbit]

Basically, you take that, put in your table names and field names. Then use that as the record source for the combo box.

[NeoPa]

This short article on SQL JOINs may help you to understand better what Rabbit is saying.