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📜  按外键计算的 sql 总数 - SQL 代码示例

📅  最后修改于: 2022-03-11 15:05:28.535000             🧑  作者: Mango

代码示例1
SELECT books.*, count(orders.book_id) as number_of_orders        
from books
left join orders
on (books.book_id = orders.book_id)
group by
    books.book_id