Confusion with length function ... ?

Question

I have avery basic question, i have a table ( Item Master ) in oracle which has a field called Item, which is declared as CHAR(50)
now this field contains data as
ITEM
Car
Pencil
Televsion
There are some 5,00,000 records in this table and i would like to find the length of data.
For example when i execute the new proposed query it should give me output as
ITEM          LENGTH
Car          3     
Pencil          6
Televsion     9
but currently when i execute the below mentioned query , it gives me output as mentioned below which i dont want
select itemcode, length(itemcode) from itemmaster;
Item          Length
Car          50
Pencil          50
Televsion     50
sorry i am new to oracle syntax, i tried to locate the excact function , but could not find :-(

Answer 1

how do i display only top 10 records descending by character length
SQL> select   object_name, len
  from   (select   object_name,
                   length (object_name) len,
                   row_number () over (order by length (object_name) desc) rn
            from   all_objects
           where   owner = 'SYS')
where   rn <= 10
OBJECT_NAME                           LEN
RESOURCE_STORAGE_POOL_MAPPING$         30
I_WRI$_OPTSTAT_H_OBJ#_ICOL#_ST         30
APPLY$_CONSTRAINT_COLUMNS_UIX1         30
V_$PGA_TARGET_ADVICE_HISTOGRAM         30
I_FGR$_FILE_GROUP_EXPORT_INFO1         30
APPLY$_CONSTRAINT_COLUMNS_IDX1         30
GV_$RSRC_CONSUME_GROUP_CPU_MTH         30
GV_$CONTROLFILE_RECORD_SECTION         30
GV_$FLASHBACK_DATABASE_LOGFILE         30
GV_$PGATARGET_ADVICE_HISTOGRAM         30
10 rows selected.