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== Find the "s" and ignore case.==



<source lang="sql">
SQL>
SQL> SELECT REGEXP_INSTR("This is a test for print SS","s",1,1,0,"i") position
2 FROM dual;
POSITION
----------
4
SQL></source>

== Occurrence refers to the first, second, third, etc., occurrence of the pattern in S. The default is 1 (first).==

Searching for the second "a" starting at position 1.



<source lang="sql">
SQL> SELECT REGEXP_INSTR("This is a test for print a","a",1,2) position
2 FROM dual;
POSITION
----------
26
SQL></source>

== Parameters is a field that may be used to define how one wants the search to proceed:==

<OL><LI>i - to ignore case</LI><LI>c - to match case</LI><LI>n - to make the metacharacter dot symbol match new lines as well as other characters (more on this later in the chapter)</LI><LI>m - to make the metacharacters ^ and $ match beginning and end of a line in a multiline string (more, later)</LI></OL>
The default is "i".
The following example finds the "s" and match case.



<source lang="sql">
SQL>
SQL> SELECT REGEXP_INSTR("This is a test for printing SS","s",1,1,0,"c") position
2 FROM dual;
POSITION
----------
4
SQL></source>

== Regexp_Instr==

REGEXP_INSTR function returns a number for the position of matched pattern.
Unlike INSTR, REGEXP_INSTR cannot work from the end of the string backward.
The arguments for REGEXP_INSTR are:



<source lang="sql">
REGEXP_INSTR(String to search, Pattern, [Position,[Occurrence, [Return-option, [Parameters]]]])</source>

== regexp_instr(comments, "[^ ]+", 1,/td>



<source lang="sql">
SQL>
SQL> create table history
2 ( empno NUMBER(4)
3 , beginyear NUMBER(4)
4 , begindate DATE
5 , enddate DATE
6 , deptno NUMBER(2)
7 , msal NUMBER(6,2)
8 , comments VARCHAR2(60)
9 ) ;
Table created.
SQL>
SQL>
SQL> insert into history values (9,2000,date "2000-01-01",date "2002-01-02",40, 950,"history for 9");
1 row created.
SQL> insert into history values (8,2000,date "2000-01-02", NULL ,20, 800,"");
1 row created.
SQL> insert into history values (7,1988,date "2000-01-06",date "2002-01-07",30,1000,"");
1 row created.
SQL> insert into history values (6,1989,date "2000-01-07",date "2002-01-12",30,1300,"");
1 row created.
SQL> insert into history values (5,1993,date "2000-01-12",date "2002-01-10",30,1500,"history for 5");
1 row created.
SQL> insert into history values (4,1995,date "2000-01-10",date "2002-01-11",30,1700,"");
1 row created.
SQL> insert into history values (3,1999,date "2000-01-11", NULL ,30,1600,"");
1 row created.
SQL> insert into history values (2,1986,date "2000-01-10",date "2002-01-08",20,1000,"history for 2");
1 row created.
SQL> insert into history values (1,1987,date "2000-01-08",date "2002-01-01",30,1000,"history for 1");
1 row created.
SQL> insert into history values (7,1989,date "2000-01-01",date "2002-05-12",30,1150,"history for 7");
1 row created.
SQL>
SQL> select comments
2 from history
3 where regexp_instr(comments, "[^ ]+", 1, 9) > 0;
no rows selected
SQL>
SQL>
SQL> drop table history;
Table dropped.
SQL>
SQL></source>

== Regexp_Instr returns the location (beginning) of a pattern in a given string==

REGEXP_INSTR extends the regular INSTR string function by allowing searches of regular expressions.
The simplest form of this function is:



<source lang="sql">
REGEXP_INSTR(source_string, pattern_to_find)</source>

== REGEXP_INSTR(x, pattern [, start [, occurrence [, return_option [, match_option]]]]) searches for pattern in x.==

REGEXP_INSTR() returns the position at which pattern occurs.
The position starts at number 1.
The following example returns the position that matches the regular expression l[[:alpha:]] {4} using REGEXP_INSTR():



<source lang="sql">
SQL> SELECT REGEXP_INSTR("abcedfghijklumnoprstuvwxyzabcedfghijklumnoprstuvwxyzabcedfghijklumnoprstuvwxyz", "l[[:alpha:]]{4}") AS result
2 FROM dual;
RESULT
----------
12
SQL></source>

== Return-option returns the position of the start or end of the matched string.==

The default is 0, which returns the starting position of the pattern in the target.
A value of 1 returns the starting position of the next character following the pattern match.



<source lang="sql">
SQL>
SQL> SELECT REGEXP_INSTR("This is a test","a",1,2,0) position
2 FROM dual;
POSITION
----------
0
SQL></source>

== Returns the position of the second occurrence that matches the letter o starting at position 10 using REGEXP_INSTR()==



<source lang="sql">
SQL>
SQL> SELECT REGEXP_INSTR("abcedfghijklumnoprstuvwxyzabcedfghijklumnoprstuvwxyzabcedfghijklumnoprstuvwxyz", "o", 10, 2) AS result
2 FROM dual;
RESULT
----------
42
SQL></source>

== Returns the position of the second occurrence that matches the regular expression s[[:alpha:]]{3} starting at position 1:==



<source lang="sql">
SQL>
SQL> SELECT REGEXP_INSTR("But, soft! What light through yonder window softly breaks?", "s[[:alpha:]]{3}", 1, 2) AS result
2 FROM dual;
RESULT
----------
45
SQL></source>

== SELECT REGEXP_INSTR("Two is bigger than One","One") where_it_is==



<source lang="sql">
2 FROM dual;
WHERE_IT_IS
-----------
20
SQL></source>

== Specify any series of letters and find matches, just like INSTR==



<source lang="sql">
SQL>
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, REGEXP_INSTR(value,"ing") where_it_is
2 FROM myTable
3 WHERE REGEXP_INSTR(value,"ing") > 0;
VALUE WHERE_IT_IS
-------------------------------------------------- -----------
1664 1/2 Springhill Ave 13
SQL>
SQL>
SQL> drop table myTable;
Table dropped.
SQL>
SQL></source>

== The Return-option is set to 1 to indicate the end of the found pattern==



<source lang="sql">
SQL>
SQL> SELECT REGEXP_INSTR("This is a test","a",1,2,1) position
2 FROM dual;
POSITION
----------
0
SQL></source>

== The simplest regular expression matches letters, letter for letter==



<source lang="sql">
SQL>
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 AAA 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 AAA Ave
7 665 Fall Ave. Linken
7 rows selected.
SQL>
SQL> SELECT value, REGEXP_INSTR(value,"Ave") where_it_is
2 FROM myTable
3 WHERE REGEXP_INSTR(value,"Ave") > 0;
VALUE WHERE_IT_IS
-------------------------------------------------- -----------
1664 1/2 AAA Ave 14
665 Fall Ave. Linken 10
SQL>
SQL> drop table myTable;
Table dropped.
SQL>
SQL></source>

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