SQL查询一个表中另外一个表不存在的数据。

SELECT COUNT(1) FROM ecs_goods LEFT JOIN ecs_member_price ON ecs_goods.goods_id=ecs_member_price.goods_id WHERE ecs_member_price.goods_id IS NULL;
#方法三：逻辑相对复杂,但是速度最快  ~执行时间: 0.570秒~
SELECT COUNT(1) FROM  ecs_goods c WHERE (SELECT COUNT(1) AS num FROM ecs_member_price WHERE ecs_member_price.goods_id=ecs_goods.goods_id) = 0;

 

例子是借用别人，个人感觉，第三种方法，比较方法比较复杂，不建议用！