การเร่งความเร็วของ LEFT JOIN และ ลำดับของฟิลด์ที่ใช้เป็น Index

SELECT C.`id`,C.`contract_no`,C.`bank_id`,P.`id_card`,N.`name`,D.`phone`,L.`court_id`,L.`black_case`,L.`red_case` 
FROM `follow_gcms`.`tbl_contract` AS C 
INNER JOIN `follow_gcms`.`tbl_person_name` AS N ON N.`contract_id` = C.`id` AND N.`customer_id` = C.`customer_id` 
INNER JOIN `follow_gcms`.`tbl_person` AS P ON P.`id` = N.`person_id` AND P.`customer_id` = C.`customer_id` 
LEFT JOIN `follow_gcms`.`tbl_person_address` AS D ON D.`name_id` = N.`id` AND N.`customer_id` = C.`customer_id` 
LEFT JOIN `follow_gcms`.`tbl_lawsuit` AS L ON L.`id` = C.`lawsuit_id` AND L.`customer_id` = C.`customer_id` 
WHERE C.`customer_id` = 1