On 5.12.2013 15:14, Tom Lane wrote:
> Ladislav Lenart <lenartlad(at)volny(dot)cz> writes:
>> What happens if I issue UPDATE SET FROM... but with incomplete/buggy WHERE
>> condition and thus SEVERAL rows from the from_list match ONE row to update?
>
> Any given row will be updated at most once. However, the from_list row
> it gets updated against will be unpredictable, depending on the
> implementation of the join.
>
> regards, tom lane
Makes perfect sense.
Thank you,
Ladislav Lenart