Question

给出两个表：

t1：包含元素的表格，
t2：另一个包含从t1

如何查询t1中尚未处理的所有元素，即t2中没有相应的pid？

为清楚起见，我正在寻找

的功能性等价物

Select * from t1 where t1.id not in (select pid from t2)

或者，一种实现简单处理队列以确定尚未处理t1中哪些新元素的方法。

更新

目前我在以下地方：

r.db("mydb").table("t1").filter( function(u) { return r.db("mydb").table("t2")("pid").contains( u("id") ).not(); })

然而，这非常低效：具体来说，它需要t2中每个元素对t1的完整表格扫描。有没有办法更有效地回报这个？

非常感谢！

Answer 1

您可以通过pid为r.table('t2').indexCreate('pid') r.table('t1').filter(function(u) { return r.table('t2').getAll(u('id'), {index: 'pid'}).isEmpty(); })：

创建二级索引来实现此目的

source 'https://rubygems.org'


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