UPDATE
t1
SET
t1.c1 = t2.c2,
t1.c2 = expression,
...
FROM
t1
[INNER | LEFT] JOIN t2 ON join_predicate
WHERE
where_predicate;
UPDATE
first_table ft
JOIN second_table st ON st.some_id = ft.some_id
JOIN third_table tt ON tt.some_id = st.some_id
.....
SET
ft.some_column = some_value
WHERE ft.some_column = 123456 AND st.some_column = 123456
UPDATE
t1
SET
t1.c1 = t2.c2,
t1.c2 = expression,
...
FROM
t1
[INNER | LEFT] JOIN t2 ON join_predicate
WHERE
where_predicate;
update A
set A.first_name = B.first_name,A.last_name = B.last_name
from dbo.tblA as A inner join dbo.tblB as B
on A.emp_id = B.emp_id
----
UPDATE A
SET A.<column_name> = B.<column_name>, ...
FROM <table_name> A
[ INNER | LEFT ] JOIN <table_name1> B ON <join_predicate>
[ WHERE Condition(s) ]
MySQL:
update ud u
inner join sale s on
u.id = s.udid
set u.assid = s.assid
----------------
SQL Server:
update u
set u.assid = s.assid
from ud u
inner join sale s on
u.id = s.udid
---------------
PostgreSQL:
update ud
set assid = s.assid
from sale s
where ud.id = s.udid;