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[程序员] 求 SQL 优化建议

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A 表 40w 数据 B 表 42W 左右, A 和 B 是一对多的关系,现在需要分页查询所以如果用 Aleft join B 数据会变多,group by 的话速度很慢, 目前用的 select * from A where exists ( select 1 from B where a.order_id = b.order_id ) 页面有些查询条件存在 A 有的存在 B ,查询条件速度很慢,B 的查询条件页面响应速度在 6s 左右,看 sql 执行需要 2.5s

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