Machform error: Cardinality violation: 1242 Subquery returns more than 1 row
We have a multiuser Machform PHP application running on a Redhat 7 Linux server with Apache webserver and MariaDB database. In a specific form after page 3, accessing this URI: confirm.php?id=NNNNNNNN&mf_page_from=3 where NNNNNNNN is the id number of the form, The following error message appears: SQL: [671] select A.element_id, A.option_id, (select if(B.element_matrix_parent_id=0,A.option, (select C.`option` from