If you are experienced in Oracle, this might be confusing since Oracle treats empty string and NULL as being the same.
> On Mon, 13 Oct 2003, Robert Partyka wrote: > >> why such condition: >> foofield not like '%bar%' >> >> where foofield is varchar >> >> returns false (or rather even ignore row) on record where foofield is >> null > > Actually, it probably returns unknown(NULL) on such records. > NULL LIKE '%bar%' is unknown, so > NULL NOT LIKE '%bar%' is also unknown. > > This is because NULL isn't the same as empty string, nor is it the > absence of a value, but it's an unknown value. > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
