Treating CHAR Values as Numeric Values

If you plan to perform calculations on numbers stored in a column, you should assign a number data type to that column. Although you can store numbers in CHAR columns, you might not be able to use them in some arithmetic operations. For example, if you insert a sum into a CHAR column, you might experience overflow problems if the CHAR column is too small to hold the value. In this case, the insert fails. Numbers that have leading zeros (such as some zip codes) have the zeros stripped if they are stored as number types INTEGER or SMALLINT. Instead, store these numbers in CHAR columns.