regr_count usage in oracle

The REGEXP_COUNT function is used to count the number of matches of a specific regular expression in a string. It receives two parameters: string and pattern, and returns the number of matches. If there is no match, 0 is returned. Other uses include checking for a match, extracting subgroups of a match, and replacing matches using the REPLACE() function.

REGEXP_COUNT Usage in Oracle

The REGEXP_COUNT function is used to count the number of matches of a specific regular expression in a string.

Syntax:

<code>REGEXP_COUNT(string, pattern)</code>

Parameters:

• string: Characters to search for string.
• pattern: Regular expression to match.

Return value:

The number of times the regular expression is matched in the string. If there is no match, 0 is returned.

Example:

<code class="sql">SELECT REGEXP_COUNT('hello world', 'o') FROM dual;</code>

Output:

<code>2</code>

Explanation: There are 2 characters "o" in the string "hello world" matching the regular expression "o".

Other uses:

The REGEXP_COUNT function can also be used:

• Check whether there is a match in the string: If the function returns 0 , meaning there is no match.
• Extract subgroups of matches: You can use the SUBSTR() function in conjunction with the REGEXP_COUNT function to extract specific subgroups of matches.
• Replace matches: You can use the REPLACE() function together with the REGEXP_COUNT function to replace specific matches in a string based on a regular expression.

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