To replicate PHP’s strip_tags() function in MySQL, this is about as close as I could get without writing a custom function. You must have MySQL >= v5.5 for this to work.

Using the REGEXP_REPLACE function:

UPDATE table_name
SET column_name = REGEXP_REPLACE(column_name, '<[^>]*>', '');

Another option for stripping HTML tags in MySQL is to use the ExtractValue function. This function can extract values from an XML document stored in a column, and can be used to remove HTML tags as well.

UPDATE table_name
SET column_name = TRIM(REPLACE(ExtractValue(column_name, '//text()'), '   ', ' '));

Note: The REPLACE() is because I kept finding that MySQL was sometimes leaving 3 spaces where it had stripped HTML.