Can anyone explain why LTRIM and RTRIM aren't trimming ASCII 32 characters? Some data has gotten messed up with trailing blanks.

Let's see if any data has leading or trailing spaces
select * from rpl_po po where strlen(po.PO) <> strlen(ltrim(rtrim(po.PO)))
Results: empty set

Let's spot check a particular item to see what it's last character is
select ascii_val(substring(po.PO from 9 for 1)) from RPL_PO po where po.ID = 3144
Results: 32

Let's test that particular item again
Select strlen(po.PO), strlen(ltrim(rtrim(po.PO)))
from RPL_PO po where po.ID = 3144
Results: 11, 11

Hmmm, let me put quotes around it in order to see leading or trailing characters
select '''' || po.PO || '''' from rpl_po po where po.ID = 3144
Results: '2895-01V   '

Let's test LTRIM and RTRIM and see what they return
select
strlen(ltrim(rtrim(' xxx '))),
ascii_val(substring(' xxx ' from 5 for 1))
from rdb$database
Results: 3, 32

Here's the table that we are using

RECREATE TABLE RPL_PO
(
ID BIGINT NOT NULL,
PO VARCHAR(16) NOT NULL,
/* snip */
CONSTRAINT PK_RPL_PO PRIMARY KEY (ID)
);