SELECT count( 0 ) FROM ( SELECT *, mt.product_id AS productId FROM mrp_tryout mt WHERE mt.company_id = 1 GROUP BY mt.product_id ) table_count

您的问题是：查询一个表中不重复的产品数量吗？

如果是的话，您可以使用以下SQL语句：

SELECT COUNT(0)
FROM (
SELECT *, mt.product_id AS productId
FROM mrp_tryout mt
WHERE mt.company_id = 1
GROUP BY mt.product_id
) AS table_count;