加入where where和less then condition

Here is my query:

这是我的查询:

$sql = "
    SELECT
        items.item_id,
        name,
        category,
        item_number,
        cost_price,
        unit_price,
         item_quantities.quantity
    FROM ospos_items
    LEFT JOIN item_quantities ON items.item_id = item_quantities.item_id
    WHERE
        deleted='0' OR item_quantities.quantity>='0'
";
$sql = "
    SELE