idselect_typetablepartitionstypepossible_keyskeykey_lenrefrowsfilteredExtra
1PRIMARYform_submissionNULLrefFK_formFK_form5const410.90Using where; Backward index scan
2DEPENDENT SUBQUERYinnerpformNULLeq_refPRIMARYPRIMARY4portal.form_submission.formId1100.00NULL