On Tue, Jun 21, 2022 at 6:33 AM Aleksander Alekseev < aleksan...@timescale.com> wrote:
> Hi David, > > > Per discussion here: > > > > > https://www.postgresql.org/message-id/163636931138.8076.5140809232053731248%40wrigleys.postgresql.org > > > > We can now easily document the array_length behavior of returning null > instead of zero for an empty array/dimension. > > > > I added an example to the json_array_length function to demonstrate that > it does return 0 as one would expect, but contrary to the SQL array > behavior. > > > > I did not bother to add examples to the other half dozen or so "_length" > functions that all produce 0 as expected. Just the surprising case and the > adjacent one. > > Good catch. > > + <literal>array_length(array[], 1)</literal> > + <returnvalue>NULL</returnvalue> > > One tiny nitpick I have is that this example will not work if used > literally, as is: > > ``` > =# select array_length(array[], 1); > ERROR: cannot determine type of empty array > LINE 1: select array_length(array[], 1); > ``` > > Maybe it's worth using `array_length(array[] :: int[], 1)` instead. > > I think subconsciously the cast looked ugly to me so I probably skipped adding it. I do agree the example should be executable though, and most of the existing examples use integer[] (not the abbreviated form, int) so I'll plan to go with that. Thanks for the review! David J.
