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dotagenius
Asked:2022-08-02 01:33:22 +0800 CST2022-08-02 01:33:22 +0800 CST

C# Linq 中此代码的 PostgreSQL 等效项

  • 772

PostgreSQL上有这个查询：

SELECT t.flight_id, COUNT(*) AS c, COALESCE(SUM(t.amount), 0) AS coal
FROM ticket_flights AS t
GROUP BY t.flight_id
HAVING COUNT(*) > 5

我不知道如何用 C# 编写它。这是我得到的：

var x = from tf in db.Ticket_Flights
    group tf by tf.Flight_Id into g
    where g.Count() > 5 
    select new { g.Key, Count = g.Count(), Sum = g ?? 0.0};

貌似前3行改写正确，但是-th有select问题。

c#

1 个回答

  1. Best Answer

    您的分组包含元素，您需要通过所需的金额字段计算它们的总和。

    var x = from tf in db.Ticket_Flights
    group tf by tf.Flight_Id into g
    where g.Count() > 5 
    select new { g.Key, Count = g.Count(), Sum = g.Sum(x => x.amount) ?? 0.0};
    • 2

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