On Fri, Jun 7, 2013 at 11:51 AM, Ryan Johnson <ryan.john...@cs.utoronto.ca>wrote:
> On 06/06/2013 10:52 AM, Gabriel Corneanu wrote: > >> In my opinion, count(*) is the same as count(rowid) (I see that even >> count() is accepted); I could say it's even the same as count(x) (any >> other >> field). >> > Not quite... count(x) only counts rows having non-NULL x. Granted, that's > not a problem for rowid/pk (which are not allowed to be NULL), but it > matters a lot in the general case. > PRIMARY KEYs (except for INTEGER PRIMARY KEYs) are allowed to be NULL in SQLite. This goes back to a bug in the code from many years ago. By the time the bug was discovered, SQLite was already in wide-spread use and so the decision was made to not fix the bug since doing so would cause compatibility problems. -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
