如何在Slick 2.0中计算(*)? [英] How to COUNT(*) in Slick 2.0?

问题描述

根据 Slick 2.0文档， 获取表中的行数:

According to the Slick 2.0 documentation, to get the count of rows in a table:

val q1 = coffees.length
// compiles to SQL (simplified):
//   select count(1) from "COFFEES"

但是，事实证明coffees.length是Column[Int]类型.

However, it turns out that coffees.length is of type Column[Int].

一个人如何执行查询并获取值?

How does one execute the query and get the value?

推荐答案

我刚刚升级到slick 2.0时遇到了同样的问题.我忘记了确切方法的用途，但是通用.run似乎对我有用，即

I just had this same problem upgrading to slick 2.0. I forget where the exact method lives, but the generic .run seems to work for me, i.e.

coffees.length.run

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