I have the following example table definitions:

Table "public.messages"

Table "public.host"

Yes, I could set Type as IP for the ip, but for this example it doesn't matter.

I run this query:

SELECT * 
FROM messages 
LEFT JOIN host ON messages.ip = host.ip;

And see this result:

I want to update all rows where there is no host name to set ignore to true. So basically, just the ignore column for this result:

SELECT * 
FROM messages 
LEFT JOIN host ON messages.ip = host.ip 
WHERE host.name IS NULL;

I can do an update for the row that does have a host name and set to true, everything works:

UPDATE messages 
SET ignore=FALSE 
FROM host 
WHERE messages.ip = host.ip AND  host.name IS NOT NULL;

UPDATE 1

SELECT * FROM messages LEFT JOIN host ON messages.ip = host.ip;

However, setting true for those that don't have a host name doesn't work.

UPDATE messages 
SET ignore=TRUE 
FROM host 
WHERE messages.ip = host.ip AND  host.name IS NULL;

UPDATE 0

I tried with a LEFT JOIN, but then everything was updated

UPDATE messages 
SET ignore=TRUE 
FROM messages m 
LEFT JOIN host h ON m.ip = h.ip 
WHERE h.name IS NULL;

UPDATE 2

SELECT * FROM messages LEFT JOIN host ON messages.ip = host.ip;

How can I update just rows without a host name?