MySQL Error Occurred

Error Message:
1021: Disk full (/var/mysqltmp/#sql_6b78_22.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")

SQL:
SELECT DISTINCT ( I.productId ), C.cat_id, I.productCode, I.description, I.image, I.price, I.name, I.popularity, I.sale_price, I.stock_level, I.useStockLevel, description,image,weight,price,pkr_list_price,amz_price,amz_list_price,name,sale_price,prod_flag,status FROM cubecart_cats_idx AS C INNER JOIN cubecart_inventory AS I ON C.productId = I.productId WHERE prod_flag=0 AND status=0 AND C.cat_id >0 AND ( I.cat_id in (1,12,13,14,15,16,17,20,21,22,23,24,25,26,28,29,31,32,33,34,35,36,37,38,30,2,3,4,5,6,7,8,9,10,11,162,163,00) OR C.cat_id in (1,12,13,14,15,16,17,20,21,22,23,24,25,26,28,29,31,32,33,34,35,36,37,38,30,2,3,4,5,6,7,8,9,10,11,162,163,00) ) GROUP BY I.productId order by productId DESC