REGEXP_INSTR

The REGEXP_INSTR function returns the start position of a regex match and searches a string for a POSIX-style regular expression. This function returns the position within the string where the match was located.

See also: REGEXP_COUNT, REGEXP_SUBSTR.

Syntax

REGEXP_INSTR( string_expr, string_test_expr [, start_index [, occurence [, return_position ]] ) --> INT

Arguments

Parameter	Description
string_expr	String to test
string_test_expr	Test pattern
start_index	The character index offset to start counting from. Defaults to 1
occurence	Which occurence to search for. Defaults to 1
return_position	Specifies the location within the string to return. Using 0, the function returns the string position of the first character of the substring that matches the pattern. A value greater than 0 returns will return the position of the first character following the end of the pattern. Defaults to 0

Test patterns

Pattern	Description
^	Match the beginning of a string
$	Match the end of a string
.	Match any character (including whitespace such as carriage return and newline)
*	Match the preceding pattern zero or more times
+	Match the preceding pattern at least once
?	Match the preceding pattern once at most
de|abc	Match either de or abc
(abc)*	Match zero or more instances of the sequence abc
{2}	Match the preceding pattern exactly two times
{2,4}	Match the preceding pattern between two and four times
[a-dX], [^a-dX]	Matches any character that is (or is not when negated with ^) either a, b, c, d, or X. The - character between two other characters forms a range that matches all characters from the first character to the second. For example, [0-9] matches any decimal digit. To include a literal ] character, it must immediately follow the opening bracket [. To include a literal - character, it must be written first or last. Any character that does not have a defined special meaning inside a [] pair matches only itself.

Returns

Integer start position of a regex match, or 0 if no match was found.

Notes

• The test pattern must be literal string. Column references or complex expressions are currently unsupported.

• If the value is NULL, the result is NULL.

Examples

For these examples, assume a table named nba, with the following structure:

CREATE TABLE nba
(
   "Name" varchar(40),
   "Team" varchar(40),
   "Number" tinyint,
   "Position" varchar(2),
   "Age" tinyint,
   "Height" varchar(4),
   "Weight" real,
   "College" varchar(40),
   "Salary" float
 );

Here’s a peek at the table contents (Download nba.csv):

nba.csv

Name	Team	Number	Position	Age	Height	Weight	College	Salary
Avery Bradley	Boston Celtics	0.0	PG	25.0	6-2	180.0	Texas	7730337.0
Jae Crowder	Boston Celtics	99.0	SF	25.0	6-6	235.0	Marquette	6796117.0
John Holland	Boston Celtics	30.0	SG	27.0	6-5	205.0	Boston University
R.J. Hunter	Boston Celtics	28.0	SG	22.0	6-5	185.0	Georgia State	1148640.0
Jonas Jerebko	Boston Celtics	8.0	PF	29.0	6-10	231.0		5000000.0
Amir Johnson	Boston Celtics	90.0	PF	29.0	6-9	240.0		12000000.0
Jordan Mickey	Boston Celtics	55.0	PF	21.0	6-8	235.0	LSU	1170960.0
Kelly Olynyk	Boston Celtics	41.0	C	25.0	7-0	238.0	Gonzaga	2165160.0
Terry Rozier	Boston Celtics	12.0	PG	22.0	6-2	190.0	Louisville	1824360.0

Find players with ‘ow’ in their name

nba=> SELECT "Name", REGEXP_INSTR("Name", 'ow') FROM nba WHERE REGEXP_COUNT("Name", 'ow')>0;
Name               | regexp_instr
-------------------+-------------
Jae Crowder        |            7
Markel Brown       |           10
Langston Galloway  |           14
Kyle Lowry         |            7
Norman Powell      |            9
Anthony Brown      |           11
Cameron Bairstow   |           15
Lorenzo Brown      |           11
Dirk Nowitzki      |            7
Dwight Powell      |            9
Dwight Howard      |            9
Justise Winslow    |           14
Karl-Anthony Towns |           15
Anthony Morrow     |           13

Using the return_position argument

Get the second occurence of the letter ‘k’ in a player’s name. We set start_index to 1 (the default)

nba=> SELECT "Name", REGEXP_INSTR("Name", 'k', 1, 2)  FROM nba WHERE REGEXP_INSTR("Name", 'k', 1, 2)>0;
Name               | regexp_instr
-------------------+-------------
Nik Stauskas       |           10
Tarik Black        |           11
Dirk Nowitzki      |           12
Sam Dekker         |            8
Kendrick Perkins   |           13
Frank Kaminsky III |           13
Nikola Jokic       |           10
Nikola Pekovic     |           10