Comments - Do not understand why MariaDB rejected REGEXP with 42000 You have an error in your SQL syntax
Content reproduced on this site is the property of its respective owners,
and this content is not reviewed in advance by MariaDB. The views, information and opinions
expressed by this content do not necessarily represent those of MariaDB or any other party.
I still do not know how to perform the trace. For example I tried the steps described on https://dbtut.com/index.php/2018/11/15/how-to-get-the-data-packets-between-mysql-client-and-server/
$ sudo tcpdump -nnei any port 8001 -w tmp.pcap [sudo] password for jcobban: tcpdump: listening on any, link-type LINUX_SLL (Linux cooked v1), capture size 262144 bytes
At this point I invoked the script http://localhost/Ontario/WmbResponse.php?district=Oxford+%26+Middlesex&area=Nissouri+Twp.E%26W which duplicated the error.
^C0 packets captured 0 packets received by filter 0 packets dropped by kernel
The error is on requests made from PHP to the MariaDB server, not on requests from the mysql client.