how to get size of table field trough oracle Query -

i want size of oracle table field(column), try below query

 select data_type, data_length    user_tab_columns  table_name = 'crm_change_req'    , column_name = 'rno';

it gives 22 real size 4,so give suggestion can do?

data_length column stores maximum length in bytes required store values datatype of given column.

for number 22 bytes, regardless of precision , scale (1 byte exponent, 20 bytes mantissa , 1 byte negative sign).

for number datatype should @ data_precision , data_scale columns if want find precision , scale defined column.

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