如何使用 Dapper 扩展谓词实现“IN”子句？

我想使用 Dapper Extensions Predicate 替换此查询？

SELECT * 
FROM SomeTable 
WHERE id IN (commaSeparatedListOfIDs)

The commaSeparatedListOfIDs is an IEnumerable of Integer.

到目前为止我已经尝试过：

using (SqlConnection cn = new SqlConnection(_connectionString))
{
    cn.Open();
    var predicate = Predicates.Field<SomeTable>(f => f.Id, Operator.???, commaSeparatedListOfIDs);
    IEnumerable<SomeTable> list = cn.GetList<SomeTable>(predicate);
    cn.Close();
}

我需要一个操作员Operator.In，但它在 Dapper Extensions 中不存在。

我应该如何使用 Dapper Extensions Predicate 系统实现“IN”子句？

解决方案一：

Using PredicateGroup with GroupOperator.Or是一种解决方案。

var predicateGroup = new PredicateGroup { Operator = GroupOperator.Or, Predicates = new List<IPredicate>() };
foreach(int thisID in commaSeparatedListOfIDs)
{
    var predicate = Predicates.Field<SomeTable>(f => f.Id, Operator.Eq, thisID);
    predicateGroup.Predicates.Add(predicate);
}
IEnumerable<SomeTable> list = cn.GetList<SomeTable>(predicateGroup);

请参考this https://github.com/tmsmith/Dapper-Extensions/issues/109 and this https://github.com/tmsmith/Dapper-Extensions/wiki/Predicates#multiple-compound-predicates-predicate-group link.

解决方案2：

正如您在回答中提到的this https://github.com/tmsmith/Dapper-Extensions/issues/164链接，使用 FieldPredicate (Predicates.Field) with Operator.Eq，并通过IEnumerable参数应该做同样的事情。

var predicate = Predicates.Field<SomeTable>(f => f.Id, Operator.Eq, commaSeparatedListOfIDs);

Here Eq应内部翻译为IN条款按照this https://github.com/tmsmith/Dapper-Extensions/blob/dd82ecc6f710bca6d5e5645cbff8da97e411257f/DapperExtensions/Predicates.cs#L203GitHub 上 Dapper Extensions 的源代码。

if(Value is IEnumerable && !(Value is string))
{
    if(Operator != Operator.Eq)
    {
        throw new ArgumentException("Operator must be set to Eq for Enumerable types");
    }

    List<string> @params = new List<string>();
    foreach(var value in (IEnumerable)Value)
    {
        string valueParameterName = parameters.SetParameterName(this.PropertyName, value, sqlGenerator.Configuration.Dialect.ParameterPrefix);
        @params.Add(valueParameterName);
    }

    string paramStrings = @params.Aggregate(new StringBuilder(), (sb, s) => sb.Append((sb.Length != 0 ? ", " : string.Empty) + s), sb => sb.ToString());
    return string.Format("({0} {1}IN ({2}))", columnName, Not ? "NOT " : string.Empty, paramStrings);
}

要转动IN如上所述的条款NOT IN子句，使用最后一个bool not范围。请参阅this https://stackoverflow.com/a/63831728/5779732回答更多详细信息。
示例代码如下：

var predicate = Predicates.Field<Customer>(f => f.CustomerID, Operator.Eq, commaSeparatedListOfIDs, true);