Count Number Of Characters In A String With MySQL

Note: This post is over two years old and so the information contained here might be out of date. If you do spot something please leave a comment and we will endeavour to correct.

30th September 2010 - 3 minutes read time

Today I needed to grab some data from a table where there was more than one occurrence of a string within another string. Basically, I needed to find all URL's from a table that were more than 3 levels deep (i.e. with 3 slashes), but realised there wasn't a function to do this in MySQL. I found an alternative method, but it got me thinking on how that might be possible.

Finding the solution wasn't too difficult really, all I needed to do was find out the length of the URL string and then subtract the length of the string with the slashes removed. This MySQL statement will give you the URL and the number of slashes in that URL in a table.

SELECT url, (LENGTH(url)-LENGTH(REPLACE(url, '/', ''))) AS depth
FROM table;

This works fine for single character string like the slash, but if you want to do the same thing with multi character strings then you need to divide the difference by the length of the string. Here is an example.

SELECT body, ROUND((LENGTH(body)-LENGTH(REPLACE(body, 'text', '')))/LENGTH('text')) AS depth
FROM table;

This will give you the number of occurrences of the word 'text' in each body field in a table.

replace

MySQL

Comments

SELECT body, ROUND((LENGTH(body)-LENGTH(REPLACE(body, 'text', '')))/LENGTH('text')) AS depth FROM table;

Submitted by Anonymous on Mon, 09/07/2015 - 12:23

Permalink

very useful.

thanks!

Submitted by claudio t. on Tue, 09/28/2021 - 19:56

Permalink

Add new comment

Related Content

Solving Query Performance Problems With The MySQL Slow Query Log

21st January 2024

MySQL's slow query log is a key component in your MySQL administration setup. Whilst normal logging can help you in terms of tracking down issues with your database system, the slow query log can help you track down issues in your database setup before they become problematic.

Creating An Authentication System With PHP and MariaDB

15th October 2023

Using frameworks to handle the authentication of your PHP application is perfectly fine to do, and normally encouraged. They abstract away all of the complexity of managing users and sessions that need to work in order to allow your application to function.

Case Insensitive Like Searches In MySQL

2nd July 2011

I needed to create a query that did a case insensitive search using the LIKE command in MySQL and I quickly realised that in order to do this I would need to alter both the parameter and the table data to be the same case. This can be done by using the MySQL UPPER() command on the table data and the strtoupper() PHP function on the input data.

Connecting To A Non Standard MySQL Socket In PHP

11th February 2011

Connecting to a MySQL database in PHP is usually not a difficult thing to do, in fact it is one of the first things that many tutorials will go though. However, there are certain curcumstances that require more information than the standard host, password and username details.

MySQL Order Table By Character Length

24th September 2009

As part of debugging a bit of code I needed to know the longest possible field lengths that a record contains. You might need to know this if you are performing a database migration. The following query returns a field, along with the length of the string, and orders the results by the number of characters in that string.

Backup MySQL Database PHP Script

12th August 2009

There are quite a few scripts available on the Internet that allow you to dump data from a database into a format that can be used to replicate that database structure elsewhere. The following function is my take on this commonly occurring script.