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| author | Bruce Momjian <bruce@momjian.us> | 2022-07-08 20:23:35 -0400 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2022-07-08 20:23:35 -0400 |
| commit | f1c779e2b9e48eab05ad471e4111eb17e7e6ad3a (patch) | |
| tree | e31573af7110660b2d9a7f67118711930e62b1a1 | |
| parent | 9d71664c88defe967ccdbf485c0216c0d5a301ee (diff) | |
| download | postgresql-f1c779e2b9e48eab05ad471e4111eb17e7e6ad3a.tar.gz postgresql-f1c779e2b9e48eab05ad471e4111eb17e7e6ad3a.zip | |
doc: add examples for array_length() and jsonb_array_length()
The examples show the output of array_length() and jsonb_array_length()
for empty arrays.
Discussion: https://postgr.es/m/CAKFQuwaoBmRuWdMLzLHDCFDJDX3wvfQ7egAF0bpik_BFgG1KWg@mail.gmail.com
Author: David G. Johnston
Backpatch-through: 13
| -rw-r--r-- | doc/src/sgml/func.sgml | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 9a177a4e8c8..6ce54c1ee1f 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -15446,6 +15446,10 @@ table2-mapping <para> <literal>json_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]')</literal> <returnvalue>5</returnvalue> + </para> + <para> + <literal>jsonb_array_length('[]')</literal> + <returnvalue>0</returnvalue> </para></entry> </row> @@ -17887,10 +17891,19 @@ SELECT NULLIF(value, '(none)') ... </para> <para> Returns the length of the requested array dimension. + (Produces NULL instead of 0 for empty or missing array dimensions.) </para> <para> <literal>array_length(array[1,2,3], 1)</literal> <returnvalue>3</returnvalue> + </para> + <para> + <literal>array_length(array[]::int[], 1)</literal> + <returnvalue>NULL</returnvalue> + </para> + <para> + <literal>array_length(array['text'], 2)</literal> + <returnvalue>NULL</returnvalue> </para></entry> </row> |