求SQL语句,一表值通过另一表更新

Question

update table2 set field4=(select field3 from table1 where table1.field1 = table2.field1 and table1.field2 = table2.field2)

Answer 1

update [table2] set [table2].[field4] = [table1].[field3] where 
[table2].[field1] = [table1].[field1] and [table2].[field2] = [table1].[field2]

Answer 2

update [table2] set [table2].[field4] = [table1].[field3] from [table1] where 
[table2].[field1] = [table1].[field1] and [table2].[field2] = [table1].[field2]