On Wed, Dec 22, 2010 at 1:41 PM, Duquette, William H (318K) < william.h.duque...@jpl.nasa.gov> wrote:
> On 12/22/10 10:35 AM, "Richard Hipp" <d...@sqlite.org> wrote: > > On Wed, Dec 22, 2010 at 1:16 PM, Duquette, William H (318K) < > william.h.duque...@jpl.nasa.gov> wrote: > > > If I define a custom SQL function in Tcl using the SQLite "$db function" > > command, is there any way to make the function return NULL? I'm guessing > > not. > > > > There is no way to get a Tcl function to return NULL, since TCL has no > concept of NULL. So, no, sadly, you cannot get an SQLite function > implemented in Tcl to return NULL. > > I imagine one could write an SQL function in C that returns NULL, > though, right? Yes. In fact, that is the default return value for SQL functions implemented in C. You have to take special actions to prevent it. > What if the API included a function null(x) that > returns NULL if x is the "nullvalue" string specified with > [$db nullvalue], and x otherwise? > You mean the "nullif()" function? http://www.sqlite.org/lang_corefunc.html#nullif > > > -- > Will Duquette -- william.h.duque...@jpl.nasa.gov > Athena Development Lead -- Jet Propulsion Laboratory > "It's amazing what you can do with the right tools." > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
