# REGEXP\$1COUNT function
<a name="REGEXP_COUNT"></a>

Searches a string for a regular expression pattern and returns an integer that indicates the number of times the pattern occurs in the string. If no match is found, then the function returns 0. 

## Syntax
<a name="REGEXP_COUNT-synopsis"></a>

```
REGEXP_COUNT ( source_string, pattern [, position [, parameters ] ] )
```

## Arguments
<a name="REGEXP_COUNT-arguments"></a>

 *source\$1string*   
A string expression, such as a column name, to be searched. 

 *pattern*   
A string literal that represents a regular expression pattern. 

 *position*   
A positive integer that indicates the position within *source\$1string* to begin searching. The position is based on the number of characters, not bytes, so that multibyte characters are counted as single characters. The default is 1. If *position* is less than 1, the search begins at the first character of *source\$1string*. If *position* is greater than the number of characters in *source\$1string*, the result is 0.

 *parameters*   
One or more string literals that indicate how the function matches the pattern. The possible values are the following:  
+ c – Perform case-sensitive matching. The default is to use case-sensitive matching.
+ i – Perform case-insensitive matching.
+ p – Interpret the pattern with Perl Compatible Regular Expression (PCRE) dialect.

## Return type
<a name="REGEXP_COUNT-return-type"></a>

Integer

## Example
<a name="REGEXP_COUNT-examples"></a>

The following example counts the number of times a three-letter sequence occurs.

```
SELECT regexp_count('abcdefghijklmnopqrstuvwxyz', '[a-z]{3}');  

 regexp_count
 --------------
            8
```

The following example counts the number of times the top-level domain name is either `org` or `edu`. 

```
SELECT email, regexp_count(email,'@[^.]*\\.(org|edu)')FROM users
ORDER BY userid LIMIT 4;

                     email                     | regexp_count
-----------------------------------------------+--------------
 Etiam.laoreet.libero@sodalesMaurisblandit.edu |            1
 Suspendisse.tristique@nonnisiAenean.edu       |            1
 amet.faucibus.ut@condimentumegetvolutpat.ca   |            0
 sed@lacusUtnec.ca                             |            0
```

The following example counts the occurrences of the string `FOX`, using case-insensitive matching.

```
SELECT regexp_count('the fox', 'FOX', 1, 'i');

 regexp_count
 --------------
            1
```

The following example uses a pattern written in the PCRE dialect to locate words containing at least one number and one lowercase letter. It uses the `?=` operator, which has a specific look-ahead connotation in PCRE. This example counts the number of occurrences of such words, with case-sensitive matching. 

```
SELECT regexp_count('passwd7 plain A1234 a1234', '(?=[^ ]*[a-z])(?=[^ ]*[0-9])[^ ]+', 1, 'p');

 regexp_count
 --------------
            2
```

The following example uses a pattern written in the PCRE dialect to locate words containing at least one number and one lowercase letter. It uses the `?=` operator, which has a specific connotation in PCRE. This example counts the number of occurrences of such words, but differs from the previous example in that it uses case-insensitive matching.

```
SELECT regexp_count('passwd7 plain A1234 a1234', '(?=[^ ]*[a-z])(?=[^ ]*[0-9])[^ ]+', 1, 'ip');

 regexp_count
 --------------
            3
```