--- Guy Fraser <guy@xxxxxxxxxxxx> wrote: > On Thu, 2005-22-09 at 21:52 -0500, Bruno Wolff III > wrote: > > On Thu, Sep 22, 2005 at 14:16:48 -0600, > > Guy Fraser <guy@xxxxxxxxxxxx> wrote: > > > On Thu, 2005-22-09 at 12:43 -0400, Greg Stark > wrote: > > > > Guy Fraser <guy@xxxxxxxxxxxx> writes: > > > > > > > > > So to answer his question he would likely > want : > > > > > > > > > > SELECT > > > > > array_upper(item,1) - array_upper(item,0) + > 1 as elements > > > > > FROM > > > > > arraytest ; > > > > > > > > Note that this doesn't work for empty arrays. > > > > It will return NULL instead of 0. > > > Your response was not at all helpfull, I would > like to > > > encourage you to expand on what I put off the > top of my > > > head. > > > > > > I have not used array_upper() before, and the > question was > > > how to return the total number of elements, not > how to > > > handle NULL and empty arrays. > > > > I think his point was that your example was going > to give the wrong answer > > for empty arrays, which is relevant to your > question. The normal way around > > that is to use the COALESCE function. > OK what I jotted down was totally wrong. > > This is slightly more correct : > > SELECT > array_upper(item,1) - array_lower(item,1) + 1 as > elements > FROM > arraytest ; > > Without do a tonne of research, I can not refine > this to handle > all circumstances. > > Can someone point me to documentation that explains > the function > better than : > > Dimensions can also be retrieved with array_upper > and array_lower, which > return the upper and lower bound of a specified > array dimension, > respectively. > > The table "Table 9-36. array Functions" does not > explain how empty > and null arrays are handled either. > > How do array_upper() and array_lower() respond to : > 1) NULL > 2) Empty Array > 3) Nonexistent requested dimension > > Also is there a function that specifies how many > dimensions the > array has? > That was exactly the answer I was looking for when I posted the question. Now if there was a function to delete a position in the array.... ie set array1 = array_delete_at(array1,5) where 5 is the position to delete __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
