SQL Join with multiple conditions

Question

I need a query to fill the column netto from table test with values from lv from table co when two conditions (test.sp= co.sp) AND (test.ver= co.ver) are given

Table test:

sp	ver	netto
A	X	Null
B	Y	Null
C	Z	Null

Table co:

sp	ver	lv
A	X	F
B	Y	G
C	Z	H

I've tried this query, but it doesn't work.

UPDATE test
SET test.netto= co.lv
FROM test
JOIN co ON (test.sp= co.sp) AND (test.ver= co.ver);

Result should be (table test):

sp	ver	netto
A	X	F
B	Y	G
C	Z	H

I get the following error message:

Error : ERROR: table name specified more than once

Answer 1

Your update statement was close.

update test
   set netto = co.lv
  from co
 where test.sp = co.sp
   and test.ver = co.ver

Output of select * from test:

A   X   F
B   Y   G
C   Z   

Where test and co were set up as:

create table test (
  sp varchar(10), 
  ver varchar(10), 
  netto varchar(10)
  );

insert into test values 
('A','X',''),
('B','Y',''),
('C','Z','');


create table co (
  sp varchar(10), 
  ver varchar(10), 
  lv varchar(10)
  );

insert into co values 
('A','X','F'),
('B','Y','G'),
('K','Z','H);