Can't execute query

SELECT product_id, 
									product.omsch as omsch,  
									details, 
									cat_id, 
									product.status as status,
									unix_timestamp(product.last_modified) as unix_last_modified,
									sscat.block_promotions,
									sscat.block_promotions as sscat_block_promotions,
									scat.block_promotions as scat_block_promotions,
									hcat.block_promotions as hcat_block_promotions
							FROM product
							LEFT JOIN categorie as sscat ON sscat.id = product.cat_id
							LEFT JOIN categorie as scat ON scat.id = sscat.catparent											
							LEFT JOIN categorie as hcat ON hcat.id = scat.catparent									
							WHERE product.actief = 1 
							AND hcat.actief = 1
							AND scat.actief = 1
							ORDER BY product.omsch LIMIT -10,20

MySQL Error: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '-10,20' at line 18

This script cannot continue, terminating.