Oracle PL/SQL/Regular Expressions/Word Start End

Add anchors or "wildcard" match characters as need be

SQL>
SQL> -- Add anchors or "wildcard" match characters as need be.
SQL>
SQL> SELECT REGEXP_INSTR("Hello","^.",2)  FROM dual;
REGEXP_INSTR("HELLO","^.",2)
----------------------------
                           0
SQL>

"$" a dollar sign is another anchoring operator and matches only the end of a string

SQL> create table TestTable(
  2    ID                    VARCHAR2(4 BYTE)         NOT NULL,
  3    Description           VARCHAR2(40 BYTE)
  4  )
  5  /
Table created.
SQL>
SQL>
SQL> insert into TestTable (ID, Description) values("1","1234 5th Street");
1 row created.
SQL> insert into TestTable (ID, Description) values("2","1 Culloden Street");
1 row created.
SQL> insert into TestTable (ID, Description) values("3","1234 Road");
1 row created.
SQL> insert into TestTable (ID, Description) values("4","33 Thrid Road");
1 row created.
SQL> insert into TestTable (ID, Description) values("5","One than another");
1 row created.
SQL> insert into TestTable (ID, Description) values("6","2003 Movie showing");
1 row created.
SQL> insert into TestTable (ID, Description) values("7","Start With Letters");
1 row created.
SQL>
SQL> select * from TestTable;
ID   DESCRIPTION
---- ----------------------------------------
1    1234 5th Street
2    1 Culloden Street
3    1234 Road
4    33 Thrid Road
5    One than another
6    2003 Movie showing
7    Start With Letters
7 rows selected.
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> -- "$" a dollar sign is another anchoring operator and matches only the end of a string.
SQL>
SQL> SELECT description, REGEXP_INSTR(description,"ing$") where_it_is
  2  FROM testTable
  3  WHERE REGEXP_INSTR(description,"ing$") > 0;
DESCRIPTION                              WHERE_IT_IS
---------------------------------------- -----------
2003 Movie showing                                16
SQL>
SQL>
SQL> drop table TestTable;
Table dropped.
SQL>
SQL>

"^" "anchoring operator" and matches the beginning of a string

SQL> create table TestTable(
  2    ID                    VARCHAR2(4 BYTE)         NOT NULL,
  3    Description           VARCHAR2(40 BYTE)
  4  )
  5  /
Table created.
SQL>
SQL>
SQL> insert into TestTable (ID, Description) values("1","1234 5th Street");
1 row created.
SQL> insert into TestTable (ID, Description) values("2","1 Culloden Street");
1 row created.
SQL> insert into TestTable (ID, Description) values("3","1234 Road");
1 row created.
SQL> insert into TestTable (ID, Description) values("4","33 Thrid Road");
1 row created.
SQL> insert into TestTable (ID, Description) values("5","One than another");
1 row created.
SQL> insert into TestTable (ID, Description) values("6","2003 Movie");
1 row created.
SQL> insert into TestTable (ID, Description) values("7","Start With Letters");
1 row created.
SQL>
SQL> select * from TestTable;
ID   DESCRIPTION
---- ----------------------------------------
1    1234 5th Street
2    1 Culloden Street
3    1234 Road
4    33 Thrid Road
5    One than another
6    2003 Movie
7    Start With Letters
7 rows selected.
SQL>
SQL>
SQL> --"^" "anchoring operator" and matches the beginning of a string. 
--The caret may also mean "not,".
SQL>
SQL> SELECT description, REGEXP_INSTR(description,"^O.e") where_it_is
  2  FROM testTable
  3  WHERE REGEXP_INSTR(description,"^O.e") > 0;
DESCRIPTION                              WHERE_IT_IS
---------------------------------------- -----------
One than another                                   1
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> drop table TestTable;
Table dropped.
SQL>
SQL>

Asking for a match for a capital "F" followed by any character

SQL> create table TestTable(
  2    ID                    VARCHAR2(4 BYTE)         NOT NULL,
  3    Description           VARCHAR2(40 BYTE)
  4  )
  5  /
Table created.
SQL>
SQL>
SQL> insert into TestTable (ID, Description) values("1","1234 5th Street");
1 row created.
SQL> insert into TestTable (ID, Description) values("2","1 Culloden Street");
1 row created.
SQL> insert into TestTable (ID, Description) values("3","1234 Road");
1 row created.
SQL> insert into TestTable (ID, Description) values("4","33 Thrid Road");
1 row created.
SQL> insert into TestTable (ID, Description) values("5","One than another");
1 row created.
SQL> insert into TestTable (ID, Description) values("6","F003 Movie");
1 row created.
SQL> insert into TestTable (ID, Description) values("7","Start With Letters");
1 row created.
SQL>
SQL> select * from TestTable;
ID   DESCRIPTION
---- ----------------------------------------
1    1234 5th Street
2    1 Culloden Street
3    1234 Road
4    33 Thrid Road
5    One than another
6    F003 Movie
7    Start With Letters
7 rows selected.
SQL>
SQL>
SQL>
SQL> -- Asking for a match for a capital "F" followed by any character
SQL>
SQL> SELECT description, REGEXP_INSTR(description,"^F.") where_it_is
  2  FROM testTable
  3  WHERE REGEXP_INSTR(description,"^F.") > 0;
DESCRIPTION                              WHERE_IT_IS
---------------------------------------- -----------
F003 Movie                                         1
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> drop table TestTable;
Table dropped.
SQL>
SQL>