I have a SQL query that does what I need SELECT ipi.*, COALESCE(unique_purchases, 0) AS unique_purchases FROM mst_inventory_planner_inventory AS ipi LEFT JOIN ( SELECT product_id, COUNT(DISTINCT order_id) AS unique_purchases FROM sales_order_item GROUP BY product_id ) AS soi ON ipi.product_id = soi.product_id; I have trouble implementing an equivalent in Grid ResourceModel. […]