SQL queries a table for data that does not exist in another table-go to

#方法一: Use not in, easy to understand, low efficiency ~ Execution Time: 1.395 seconds ~
Select COUNT (1) from Ecs_goods WHERE ecs_goods.goods_id not in (SELECT ecs_member_price.goods_id from Ecs_member_price);
#方法二: Use left Join...on ..., "b.id isnull" indicates a record of NULL in the b.ID field after the connection is connected-execution time: 0.739 seconds ~
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: Logic is relatively complex, but fastest ~ execution time: 0.570 seconds ~
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;

SQL queries a table for data that does not exist in another table-go to