Activities Query

$query = $this->db->query("
    SELECT 
        (
            COALESCE(Rep_Qty, 0) +
            COALESCE(Rep_Qty_Delivered, 0) +
            COALESCE(Order_Qty, 0) +
            COALESCE(Sales_Qty, 0) +
            COALESCE(Returns_Qty, 0) +
            COALESCE(Shipment_Qty, 0) +
            (COALESCE(Purchase_Qty, 0) * 0.25) +
            COALESCE(SMP_Total_Offers, 0) +
            COALESCE(QC_Count, 0)
        ) / NULLIF(Working_Days, 0) AS Activities_per_Day
    FROM (
        SELECT
            (SELECT COUNT(DISTINCT page_id) FROM isellpt_isystem_new.tbl_status_history WHERE page = 'repairs' AND status_text LIKE '%Add New%') AS Rep_Qty,
            (SELECT COUNT(DISTINCT page_id) FROM isellpt_isystem_new.tbl_status_history WHERE page = 'repairs' AND status_text LIKE '%Delivered%') AS Rep_Qty_Delivered,
            (SELECT COUNT(DISTINCT page_id) FROM isellpt_isystem_new.tbl_status_history WHERE page = 'clientorders' AND status_text LIKE '%Processing%') AS Order_Qty,
            (SELECT COUNT(DISTINCT id) FROM isellpt_isystem_new.tbl_sales WHERE created_date1 IN (SELECT Date FROM isellpt_isystem_new.'1. Dates 2.0') AND status = 'complete') AS Sales_Qty,
            (SELECT COUNT(DISTINCT id) FROM isellpt_isystem_new.tbl_returns WHERE created_date1 IN (SELECT Date FROM isellpt_isystem_new.'1. Dates 2.0') AND status <> 'delete') AS Returns_Qty,
            (SELECT COUNT(DISTINCT id) FROM isellpt_isystem_new.tbl_deliveries WHERE status = 1) AS Shipment_Qty,
            (SELECT SUM(quantity) FROM isellpt_isystem_new.tbl_stocklog WHERE type = 'Purchase' AND action = 'increase') AS Purchase_Qty,
            (SELECT COUNT(DISTINCT page_id) FROM isellpt_isystem_new.tbl_status_history WHERE page = 'buybackhistory' AND status_text LIKE '%Oferta submetida%') AS SMP_Total_Offers,
            (SELECT COUNT(*) FROM isellpt_isystem_new.tbl_status_history WHERE QC_Status IS NOT NULL) AS QC_Count,
            (SELECT COUNT(*) FROM isellpt_isystem_new.'1. Dates 2.0' WHERE IsWorkingDay = 1) AS Working_Days
    ) AS SubMeasures;
");

return $query->row();