compare case and nullif

aaa.sql

create or replace function aaa(aaa integer)
    returns text as $$
begin
    raise notice 'passed1';
    return aaa :: text || '😼';
end
$$ language 'plpgsql' strict;

select case when aaa(1) = '1'
    then null
       when aaa(1) = '3'
           then null
       else aaa(1) end;

select nullif(nullif(aaa(1), '1'), '3');


[local] gis@gis=# create or replace function aaa(aaa integer)
[more] - >     returns text as $$
[more] $ > begin
[more] $ >     raise notice 'passed1';
[more] $ >     return aaa :: text || '😼';
[more] $ > end
[more] $ > $$ language 'plpgsql' strict;
CREATE FUNCTION
Time: 0,672 ms
[local] gis@gis=# 
[local] gis@gis=# select case when aaa(1) = '1'
[more] - >     then null
[more] - >        when aaa(1) = '3'
[more] - >            then null
[more] - >        else aaa(1) end;
NOTICE:  00000: passed1
LOCATION:  exec_stmt_raise, pl_exec.c:3165
NOTICE:  00000: passed1
LOCATION:  exec_stmt_raise, pl_exec.c:3165
NOTICE:  00000: passed1
LOCATION:  exec_stmt_raise, pl_exec.c:3165
┌─────┐
│ aaa │
├─────┤
│ 1😼  │
└─────┘
(1 row)

Time: 0,492 ms
[local] gis@gis=# 
[local] gis@gis=# select nullif(nullif(aaa(1), '1'), '3');
NOTICE:  00000: passed1
LOCATION:  exec_stmt_raise, pl_exec.c:3165
┌────────┐
│ nullif │
├────────┤
│ 1😼     │
└────────┘
(1 row)

Time: 0,292 ms