I'm sorry.
This is my mistake. My way was wrong.
PostgreSQL is processing in accordance with the specification
Thank you for your reply despite being so busy.
On Wed, 12 Mar 2014 10:29:25 -0400
Tom Lane <tgl@sss.pgh.pa.us> wrote:
| uehara.kazuki@po.ntts.co.jp writes:
| > Depending on the version, the result of the TRIM function is different.
|
| I'm not sure that anyone would consider this a supported thing to do:
|
| > CREATE FUNCTION LTRIM(CHAR,text)
| > RETURNS text
| > AS 'ltrim'
| > LANGUAGE internal
| > STRICT;
|
| My attitude towards overriding system functions like that is "if it
| breaks, you get to keep both pieces". (BTW, is there a reason you
| omitted IMMUTABLE from this?)
|
| However,
|
| > PostgreSQL9.3.3：
| > | postgres=# SELECT '|' || TRIM(LEADING 'a' FROM 'abcd'::char(7)) || '|';
| > | ?column?
| > | ----------
| > | |bcd |
| > | (1 row)
|
| I get "|bcd|" from this example, in both 9.3 and HEAD branch. I would
| be surprised to get anything different, because the grammar converts
| that syntax into "pg_catalog.ltrim(..., ...)" and so your override
| function cannot be selected as the expansion. At least not if the
| override function went into schema "public", which would be the default.
|
| I suspect that in 9.3.3 you forced the function into the pg_catalog
| schema, but omitted to do that in the other two examples.
|
| regards, tom lane
--
Kazuki Uehara
uehara.kazuki@po.ntts.co.jp