have you any wool?

Updating a table with values from a Joined table.

I run into this question from the guys at work quite a bit, but it’s actually a pretty easy concept once you get the hang of it. If you have two tables that you want to sync values on, and you have a primary/foreign key you can join on, you’re all set.

Update Table1
Set Table1.ThisNeedsUpdated = Table2.WithThisNewValue
From Table1
Inner Join Table2 on Table1.ID = Table2.ID

If you get stuck, just remember a few things.

• The table in your “Update” caluse should be the same table in your “From” clause.
• You can join additional tables, nested selects or common table expressions as well and update your main table with values from those as well.
• If you’re working with two tables that have similiar field names, it’s best to fully qualify those fields in your statement to make it more readable.

Please comment if you have any questions or can’t get this working. I’d be glad to help.