Обсуждение: Array functions, array_length behavior given an empty array
The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/13/functions-array.html Description: For whom it may concern, I'd like to propose an extension for `array_length` function description. Currently, it does not cover the case of an empty array: https://www.postgresql.org/docs/13/functions-array.html Table 9.52. Array Functions. Row 5 The description reads as `Returns the length of the requested array dimension.` For me, an expected result for an empty array would be `0`, but it is `NULL`. Tested on `PostgreSQL 13.4` with query `SELECT ARRAY_LENGTH(ARRAY[]::CHARACTER VARYING[],1);` I believe, such case deserves to be mentioned in the description and/or in examples. With best regards, Oleg Rekin
Hi
po 8. 11. 2021 v 13:48 odesílatel PG Doc comments form <noreply@postgresql.org> napsal:
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/13/functions-array.html
Description:
For whom it may concern,
I'd like to propose an extension for `array_length` function description.
Currently, it does not cover the case of an empty array:
https://www.postgresql.org/docs/13/functions-array.html
Table 9.52. Array Functions. Row 5
The description reads as `Returns the length of the requested array
dimension.`
For me, an expected result for an empty array would be `0`, but it is
`NULL`.
Tested on `PostgreSQL 13.4` with query `SELECT
ARRAY_LENGTH(ARRAY[]::CHARACTER VARYING[],1);`
I believe, such case deserves to be mentioned in the description and/or in
examples.
you can read related discussion https://pgsql-hackers.postgresql.narkive.com/lZJQ64dp/array-length-anyarray
Use instead function cardinality
Regards
Pavel Stehule
With best regards,
Oleg Rekin
On Monday, November 8, 2021, Pavel Stehule <pavel.stehule@gmail.com> wrote:
Hipo 8. 11. 2021 v 13:48 odesílatel PG Doc comments form <noreply@postgresql.org> napsal:The following documentation comment has been logged on the website:
I believe, such case deserves to be mentioned in the description and/or in
examples.you can read related discussion https://pgsql-hackers.postgresql.narkive.com/ lZJQ64dp/array-length-anyarray Use instead function cardinality
I believe the OP has a point that we could do better with the documentation though. Especially now that we’ve performed the function table reformatting.
David J.
po 8. 11. 2021 v 18:11 odesílatel David G. Johnston <david.g.johnston@gmail.com> napsal:
On Monday, November 8, 2021, Pavel Stehule <pavel.stehule@gmail.com> wrote:Hipo 8. 11. 2021 v 13:48 odesílatel PG Doc comments form <noreply@postgresql.org> napsal:The following documentation comment has been logged on the website:
I believe, such case deserves to be mentioned in the description and/or in
examples.you can read related discussion https://pgsql-hackers.postgresql.narkive.com/lZJQ64dp/array-length-anyarrayUse instead function cardinalityI believe the OP has a point that we could do better with the documentation though. Especially now that we’ve performed the function table reformatting.
+1
Pavel
David J.