How can I do an UPDATE statement with JOIN in SQL Server?

Question

I need to update this table in SQL Server with data from its \'parent\' table, see below:

Table: sale

id (int)
udid         


        

Answer 1

Teradata Aster offers another interesting way how to achieve the goal:

MERGE INTO ud --what trable should be updated
USING sale -- from what table/relation update info should be taken
ON ud.id = sale.udid --join condition
WHEN MATCHED THEN 
    UPDATE SET ud.assid = sale.assid; -- how to update