c# - 如何将所有记录合并为 2 条记录并删除所有未合并的记录？

Question

我使用以下代码合并(使用逗号)具有相同 Symptom_Type 的输入记录。现在的问题是我可以将记录合并并插入数据库，但是如何从“nPG_Chemical.NPG_Chemical_Symptoms”中删除那些未合并的记录？

var SymptomType = nPG_Chemical.NPG_Chemical_Symptoms.GroupBy(Type => Type.Symptom_Type);
foreach (var type in SymptomType)
{
    var text = String.Join(", ", type.Select(x => x.Symptom_Text.ToString()).ToArray());
    nPG_Chemical.NPG_Chemical_Symptoms.Add(new NPG_Chemical_Symptom
    {
        Symptom_Type = type.Key.ToString(),
        Symptom_Text = text
    });

    db.SaveChanges();
}

Answer 1

我不确定我是否正确理解了您的要求。似乎你想要的只是

After you have combined records by Symptom_Type, and inserted them into database, you want to delete the original records.

如果这是你想要的，你可以这样做

db.YourTable
    .RemoveRange(db.YourTable
                    .Where(x => !x.Symptom_Text.Contains(",")));