Oracle PL/SQL/Data Type/Cast

CAST(x AS type_name): Converts a value in x from one data type to another specified in type_name

SQL> -- CAST(x AS type_name): Converts a value in x from one data type to another 
specified in type_name.
SQL> select cast("1234" as Number) from dual;
CAST("1234"ASNUMBER)
--------------------
                1234
SQL>