/// <summary>
/// 返回首列结果
/// </summary>
/// <typeparam name="TModel"></typeparam>
/// <param name="query"></param>
/// <returns></returns>
public dynamic QueryScalar <TModel>(LambdaQuery <TModel> query) where TModel : IModel, new()
{
query.Top(1);
var reader = GetQueryDynamicReader(query);
var a = reader.Read();
if (!a)
{
return(null);
}
var result = reader[0];
reader.Close();
return(result);
}
/// <summary>
/// 查询返回单个结果
/// 如果只查询ID,调用QueryItem(id)
/// </summary>
/// <typeparam name="TItem"></typeparam>
/// <param name="expression"></param>
/// <param name="idDest">是否按主键倒序</param>
/// <param name="compileSp">是否编译成存储过程</param>
/// <returns></returns>
public TItem QueryItem <TItem>(Expression <Func <TItem, bool> > expression, bool idDest = true, bool compileSp = false) where TItem : IModel, new()
{
LambdaQuery <TItem> query = new LambdaQuery <TItem>(this);
query.Top(1);
query.Where(expression);
query.OrderByPrimaryKey(idDest);
List <TItem> list = QueryList <TItem>(query, 0, compileSp);
if (list.Count == 0)
{
return(null);
}
return(list[0]);
}