customers_group_id int default(0) not_null comment(FK to customers_groups table - customer group identifier)
categories_id int default(0) not_null comment(FK to categories table - category identifier)
discount decimal(11,2) default(0.00) not_null comment(Discount percentage for this customer group on this category - e.g. 10.00 for 10% off)
--
primary customers_group_id categories_id
##
engine innodb
character_set utf8mb4
collate utf8mb4_unicode_ci