How Can I Count Items in a Comma-Separated List Using MySQL?

Counting Items in Comma-Separated Lists with MySQL

In MySQL, you may encounter a need to determine the number of items stored in a comma-separated list within a database column. To address this challenge, you can leverage a straightforward technique involving string manipulation and length comparisons.

The proposed solution centers around calculating the difference between the length of the original comma-separated list and the length of the same string with commas removed. This difference precisely represents the count of items in the list.

The formula used is:

LENGTH(fooCommaDelimColumn) - LENGTH(REPLACE(fooCommaDelimColumn, ',', ''))

Here's an illustration:

SELECT LENGTH('cats,dogs,cows') - LENGTH(REPLACE('cats,dogs,cows', ',', '')) AS listCount

This query would return 4, as the original string has 4 items separated by commas and the trailing comma present in the original string is accounted for in the formula.

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