GROUP BY Using,Join/Combine two table when export Mysql data to Excel Download? -

let me know how use group oc_product.product_id when export mysql data excel downloading.

select     t1.product_id,     t2.name,     t3.category_id oc_product t1 inner join oc_product_description t2     on t1.product_id = t2.product_id inner join oc_product_to_category t3     on t1.product_id = t3.product_id     t1.status=1 , t2.name '%".$desp."%'