Update sku_weight_discount view for performance improvement

db/views/sku_weight_discount.sql

@@ -1,7 +1,9 @@
 CREATE OR REPLACE VIEW sku_weight_discount_service_fees AS
 SELECT s.id,
        s.erp_code,
-       (SELECT sw.weight FROM sku_weight sw WHERE sw.sku_id = s.id ORDER BY effective_date DESC LIMIT 1) as weight,
+       sw.weight,
        s.shipping_discount,
        s.service_fee
-FROM sku s
+FROM sku_weight sw inner join (select sku_id, max(effective_date) max_date from sku_weight group by sku_id) sw2
+    on sw.sku_id = sw2.sku_id and sw.effective_date = sw2.max_date
+join sku s on sw.sku_id = s.id