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我需要在我的数据库中有一列由数据库计算为(行数之和) - (行数b).我正在使用代码优先模型来创建我的数据库.

这就是我的意思:

public class Income {
      [Key]
      public int UserID { get; set; }
      public double inSum { get; set; }
}

public class Outcome {
      [Key]
      public int UserID { get; set; }
      public double outSum { get; set; }
}

public class FirstTable {
      [Key]
      public int UserID { get; set; }
      public double Sum { get; set; } 
      // This needs to be calculated by DB as 
      // ( Select sum(inSum) FROM Income WHERE UserID …