Update field to a column from another table

["drum.lucas@xxxxxxxxx" <drum.lucas@xxxxxxxxx>]

I've got two tables:

- ja_jobs

- junk.ja_jobs_23856

I need to update the null column ja_jobs.time_job with the data from the table  junk.ja_jobs_23856

So I'm doing:

UPDATE public.ja_jobs AS b
SET   time_job = a.time_job
FROM junk.ja_jobs_23856 AS a
WHERE a.id = b.id
AND a.clientid = b.clientid;

But it's now working... I'm using PostgreSQL 9.2

Do you guys have an idea why?

cheers;

Lucas