To_char in 10g and 11g

Question

Hi I am running a select query with to_char conversion in the where field but it is not giving any output even though there are rows for the specified value. to do with itBut I am getting output in 11g..Does characterset has anything

Answer 1

You've defined the column as a CHAR.  That would make it a fixed-width column.  The value '2' inserted would have two blanks appended (rpadded) to it.  So, the resulting string cannot be compared to '2'.
Use VARCHAR2.
See the demo.  Note the difference in the number of characters stored (VSIZE):
SQL> create table hkc_test_10 (id char(3));
Table created.
SQL> insert into hkc_Test_10 values ('2');
1 row created.
SQL> select vsize(id) from hkc_Test_10;
VSIZE(ID)
         3
1 row selected.
SQL> create table hkc_test_11 (id varchar2(3));
Table created.
SQL> insert into hkc_test_11 values ('2');
1 row created.
SQL> select vsize(id) from hkc_test_11;
VSIZE(ID)
         1
1 row selected.
SQL> select * from hkc_test_11 where id = to_char(2);
ID
2
1 row selected.
SQL> select * from hkc_test_11 where id = to_char(002);
ID
2
1 row selected.
SQL>
Hemant K Chitale