Lpad .. correct use to right justify a char field?

Question

Hi all,
I have a column that's a char type, and I'm trying to manipulate justification within it.
SQL> create table test (test char(14));
Table created.
SQL> insert into test values (' 001234567890');
1 row created.
SQL> select * from test;
TEST
001234567890
..I have no probs making it left justified using ltrim
SQL> update test set test=ltrim(test);
1 row updated.
SQL> select * from test;
TEST
001234567890
...but when I try to right justify using lpad I can't get it to work:
SQL> update test set test=lpad(test,14,' ');
1 row updated.
SQL> select * from test;
TEST
001234567890
..this should pad the column with blanks to make the string 14 in length right?
What am I doing wrong?
Thanks !
Adam

Answer 1

Hi, Adam,
A CHAR (14) column is always 14 characters long. If you insert a shorter string, it is automatically RPADded.
If LENGTH (test) = 14, then
lpad(test,14,' ')
simply returns test. So your UPDATE statement is equivalent to
update test set test= test;
Every row will get UPDATEd, but nothing will get changed.
To have the strings left-padded, use LPAD before INSERTing, or use UPDATE wtih LPAD and TRIM, like this:
UPDATE  test
SET     test = LPAD ( RTRIM (test)
                    , 14
                    );