请推荐一下合成生物学的资料# Biology - 生物学
h*n
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table Orders:
primary key order_id, foreign key customer_id
table Customers:
primary key customer_id, name, address
find out if there's any customer not having any order.
single query, and no nested query allowed.
primary key order_id, foreign key customer_id
table Customers:
primary key customer_id, name, address
find out if there's any customer not having any order.
single query, and no nested query allowed.