regexp_instr() Function - (MySQL Regular Expressions)

The regexp_instr() function is a regular expression function in MySQL that returns the position of the first occurrence of a regular expression pattern in a string. In this tutorial, we'll discuss the syntax, example, output, explanation, use, important points, and summary of the regexp_instr() function.

Syntax

The syntax for the regexp_instr() function is as follows:

SELECT REGEXP_INSTR(string, pattern)

Here, "string" is the string to search, and "pattern" is the regular expression pattern to search for. The function returns the position of the first occurrence of the pattern in the string, or 0 if the pattern is not found.

Example

Let's say we have a table called "employees" with a column called "name". We want to find the position of the first occurrence of the letter "o" in each name. Here's how we can do that using the regexp_instr() function:

SELECT REGEXP_INSTR(name, 'o') AS position FROM employees;

Output

When we run the example code above, we'll get a result set that looks something like this:

position
-------
2
4
1
0

This tells us that the first occurrence of the letter "o" in the name "John" is in the second position, the first occurrence in the name "Bob" is in the fourth position, and so on. The final row has a position of 0 because the letter "o" is not found in the name "Sophie".

Explanation

In the example above, we used the regexp_instr() function to find the position of the first occurrence of the letter "o" in each name in the "employees" table. The function works by searching for the regular expression pattern "o" in each name and returning the position of the first occurrence of that pattern.

Use

The regexp_instr() function can be used to find the position of the first occurrence of a regular expression pattern in a string. It can be useful for tasks such as data cleansing, pattern matching, and data validation.

Important Points

• The regexp_instr() function is case-sensitive by default, but you can make it case-insensitive by using the i flag in the pattern.
• If the pattern is not found in the string, the function returns 0.
• If the pattern is found in the string, the function returns the position of the first occurrence of the pattern.

Summary

In this tutorial, we discussed the syntax, example, output, explanation, use, and important points of the regexp_instr() function in MySQL. With this knowledge, you can now use the regexp_instr() function to find the position of the occurrence of a regular expression pattern in a string in your MySQL projects.