简单的SQL到Linq查询，具有分组和汇总功能 [英] Simple sql to Linq query with group by and aggregate functions

问题描述

我正在与linq尝试学习语法，但我不知道如何执行以下简单查询

I'm fighting with linq trying to learn the syntax and I can't figure out how to do the following simple query

SELECT DISTINCT
    user.firstname,
    user.lastname,
    COUNT(invoice.amount),
    SUM(invoice.amount)
FROM
    company_user
    INNER JOIN 
        user
    ON 
        company_user.user_id = user.user_id
    INNER JOIN 
        invoice
    ON
        invoice.user_id= invoice.user_id
WHERE 
    company_user.company_id = 1
GROUP BY
    user.firstname,
    user.lastname,
GO

将其转换为linq的任何帮助都会很棒.

Any help turning this into linq would be great.

推荐答案

您要查询的内容应与此非常接近:

The query you're after should be pretty close to this:

var query =
    from cu in company_user
    where cu.company_id == 1
    join u in user on cu.user_id equals u.user_id
    join i in invoice on u.user_id equals i.user_id
    group i.amount by new
    {
        u.firstname,
        u.lastname,
    } into gs
    select new
    {
        firstname = gs.Key.firstname,
        lastname = gs.Key.lastname,
        count = gs.Count(),
        sum = gs.Sum(),
    };

享受！

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