The bracketed expression [[:digit]] matches numbers : Bracketed Special Classes « Regular Expressions Functions « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. Regular Expressions Functions
3. Bracketed Special Classes

If we wanted to find all rows that begin with a number:

SQL> -- create demo table
SQL> create table myTable(
  2    id           NUMBER(2),
  3    value        VARCHAR(50)
  4  );

Table created.

SQL>
SQL> insert into myTable(id, value)values(1,'1234 4th St. Vancouver');

1 row created.

SQL> insert into myTable(id, value)values(2,'4 Maple Ct. New York');

1 row created.

SQL> insert into myTable(id, value)values(3,'4321 Green Blvd. London');

1 row created.

SQL> insert into myTable(id, value)values(4,'33 Third St. Toronto');

1 row created.

SQL> insert into myTable(id, value)values(5,'One First Drive. Queen');

1 row created.

SQL> insert into myTable(id, value)values(6,'1664 1/2 Springhill Ave');

1 row created.

SQL> insert into myTable(id, value)values(7,'665 Fall Ave. Linken');

1 row created.

SQL>
SQL> select * from mytable;

        ID VALUE
---------- --------------------------------------------------
         1 1234 4th St. Vancouver
         2 4 Maple Ct. New York
         3 4321 Green Blvd. London
         4 33 Third St. Toronto
         5 One First Drive. Queen
         6 1664 1/2 Springhill Ave
         7 665 Fall Ave. Linken

7 rows selected.

SQL>
SQL>
SQL> SELECT value
  2  FROM myTable
  3  WHERE REGEXP_INSTR(value,'^[[:digit:]]') = 1;

VALUE
--------------------------------------------------
1234 4th St. Vancouver
4 Maple Ct. New York
4321 Green Blvd. London
33 Third St. Toronto
1664 1/2 Springhill Ave
665 Fall Ave. Linken

6 rows selected.

SQL>
SQL>
SQL> drop table myTable;

Table dropped.

SQL>
SQL>
SQL>