Synopsis

This is not strictly a regular expression error. However, you can get this error if you pass an invalid match_parameter to one of the REGEXP functions. See Section 1.7.3 in Section 1.7 for more details.

You can also get this error by passing an invalid type for any parameter. For example, you’ll get this error if you pass a number where a string is expected, or vice-versa.

If you do get this error as the result of a call to one of the REGEXP functions, check to be sure that all your argument types are valid, and that you are passing only valid matching options ('i', 'c', 'm', or 'n') in your match_parameter argument, which is always the last argument of a REGEXP function call.