题解 | #列出供应商及其可供产品的数量#
列出供应商及其可供产品的数量
https://www.nowcoder.com/practice/17f22851cf204019b51a36761a3afc79
select Vendors.vend_id, if(p.prod_id is null,0,p.prod_id) from Vendors left join (select vend_id,count(prod_id) as prod_id from Products group by vend_id) as p on Vendors.vend_id=p.vend_id order by Vendors.vend_id asc
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