mysql - 不带 in 的两个条件查询

Question

我有一个如下查询

select * from conv_master cm  
where cm.`from_currency_id` in (select currency_id from currency_master where currency_code = 'USD')
and cm.to_currency_id in (select currency_id from currency_master where currency_code = 'EUR');

有没有办法在不使用in的情况下重写这个查询。谢谢

Answer 1

尝试这个查询:

select * from conv_master cm 
inner join currency_master m1  on cm.from_currency_id = m1.currency_id
inner join currency_master m2  on cm.to_currency_id = m2.currency_id
where m1.currency_code='USD' and m2.currency_code='EUR'