How to Search for Specific Values in a Comma-Separated Field in MySQL?

Searching within a Comma-Separated Field in MySQL

In MySQL, certain scenarios may arise where data is stored in a comma-separated format, despite recommended practices advising against it. This poses challenges when attempting to perform precise searches within such fields. Consider the following example:

A table contains a field with values from another table stored as a comma-separated list:

12,13,14,16

The task at hand is to search for specific values within this field using a query like:

SELECT ... WHERE field LIKE '%1%'

However, due to the nature of the data, such a query would match nearly all entries, as most common IDs fall within a narrow range.

To address this issue, a more specific search is required. Instead of using %1%, consider using %,1,% within the LIKE condition. This will match values that contain 1 preceded and followed by a comma.

Unfortunately, this approach has limitations for the first and last values in the comma-separated list, as they will not be matched by the pattern.

Therefore, a different approach is necessary. MySQL provides a powerful function called FIND_IN_SET, which allows one to search within a comma-separated list:

SELECT ... WHERE FIND_IN_SET('1', field)

Using FIND_IN_SET will return the position of the specified value within the comma-separated list, or 0 if the value is not present. This enables precise and efficient searches even in non-ideal data structures.

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