dapper

查询数据库是否存在数据
select isnull((select top(1) 1 from Menu where ParentId=@ParentId and Deleted='false'),0)

select count(1) from Sys_Admin where 1=1 

publicList<MSys_Admin>GetAdminList(MSys_Admin model)  
{  
    string sqlText ="select count(1) from Sys_Admin where 1=1";  
    var p =newDynamicParameters();  
    if(!string.IsNullOrEmpty(model.LoginName))  
        {  
            sqlText +=" and LoginName like @LoginName";  
            p.Add("LoginName", model.LoginName+"%");  
        }  
    if(!string.IsNullOrEmpty(model.Name))  
        {  
            sqlText +=" and Name like @Name";  
            p.Add("Name","%"+ model.Name+"%");  
        }  
    using(var conn =Common.GetConn())  
    {  
        conn.Open();  
        var r = conn.Query<MSys_Admin>(sqlText, p);  
        conn.Close();  
        return r.ToList();  
     }  
}      

 工具类

/// <summary>
        /// 查询操作
        /// </summary>
        /// <typeparam name="T">返回集合的类型</typeparam>
        /// <param name="sql">sql语句</param>
        /// <param name="param">参数化值</param>
        /// <returns></returns>
        public IEnumerable<T> Query<T>(string sql, object param)
        {
            IEnumerable<T> _list = default(IEnumerable<T>);
            if (!string.IsNullOrEmpty(sql))
            {
                try
                {
                    _list = DbConnection.Query<T>(sql, param);
                }
                catch { }
            }
            return _list;
        }

        /// <summary>
        /// 执行存储过程查询操作
        /// </summary>
        /// <typeparam name="T">返回集合的类型</typeparam>
        /// <param name="storedName">存储过程</param>
        /// <param name="param">参数化值</param>
        /// <returns></returns>
        public IEnumerable<T> QueryStored<T>(string storedName, object param)
        {
            IEnumerable<T> _list = default(IEnumerable<T>);
            if (!string.IsNullOrEmpty(storedName))
            {
                try
                {
                    _list = DbConnection.Query<T>(storedName,commandType: CommandType.StoredProcedure);
                }
                catch { }
            }
            return _list;
        }

        /// <summary>
        /// 查询操作返回默认第一条数据(如返回null则创建默认类型)
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="sql"></param>
        /// <param name="param"></param>
        /// <returns></returns>
        public T FirstOrDefault<T>(string sql, object param)
        {
            var model = default(T);
            if (!string.IsNullOrEmpty(sql))
            {
                try
                {
                    model = DbConnection.Query<T>(sql, param).FirstOrDefault();
                }
                catch { }
            }
            return model == null ? Activator.CreateInstance<T>() : model;
        }



        /// <summary>
        /// 查询一组SQL语句并返回值
        /// </summary>
        /// <typeparam name="T1">第一条语句返回集合类型</typeparam>
        /// <typeparam name="T2">第二条语句返回集合类型</typeparam>
        /// <param name="sql">sql语句</param>
        /// <param name="param">参数化值</param>
        /// <returns></returns>
        public Tuple<IEnumerable<T1>, IEnumerable<T2>> Query<T1, T2>(string sql, object param)
        {
            IEnumerable<T1> _item1 = null; IEnumerable<T2> _item2 = null;
            if (!string.IsNullOrEmpty(sql))
            {
                try
                {
                    using (var multi = DbConnection.QueryMultiple(sql, param))
                    {
                        _item1 = multi.Read<T1>();
                        _item2 = multi.Read<T2>();
                    }
                }
                catch { }
            }
            return Tuple.Create<IEnumerable<T1>, IEnumerable<T2>>(_item1, _item2);
        }

        /// <summary>
        /// 查询一组SQL语句并返回值
        /// </summary>
        /// <typeparam name="T1">第一条语句返回集合类型</typeparam>
        /// <typeparam name="T2">第二条语句返回集合类型</typeparam>
        /// <typeparam name="T3">第三条语句返回集合类型</typeparam>
        /// <param name="sql">sql语句</param>
        /// <param name="param">参数化值</param>
        /// <returns></returns>
        public Tuple<IEnumerable<T1>, IEnumerable<T2>, IEnumerable<T3>> Query<T1, T2, T3>(string sql, object param)
        {
            IEnumerable<T1> _item1 = null; IEnumerable<T2> _item2 = null; IEnumerable<T3> _item3 = null;
            if (!string.IsNullOrEmpty(sql))
            {
                try
                {
                    using (var multi = DbConnection.QueryMultiple(sql, param))
                    {
                        _item1 = multi.Read<T1>();
                        _item2 = multi.Read<T2>();
                        _item3 = multi.Read<T3>();
                    }
                }
                catch { }
            }
            return Tuple.Create<IEnumerable<T1>, IEnumerable<T2>, IEnumerable<T3>>(_item1, _item2, _item3);
        }



        public void Dispose()
        {
            if (dbConnection != null)
            {
                try
                {
                    bool isClosed = dbConnection.State == ConnectionState.Closed;
                    if (!isClosed) dbConnection.Close();
                    //dbConnection.Dispose();
                }
                catch { }
            }
        }
    }

/// <summary>
/// 批量插入数据
/// </summary>
/// <param name="persons"></param>
/// <returns>影响行数</returns>
public static int Insert(List<User> users)
{
　　using (IDbConnection connection = new SqlConnection(connectionString))
　　{　　
　　    connection.Execute("insert into User(ID,Name) values(@ID,@Name)", users);
 　　} 
}

 查询的In操作：

public static List<User> QueryIn(List<Id> Ids)
{
　　using (IDbConnection connection = new SqlConnection(connectionString))
　　{
    var sql = "select * from Person where id in @ids";
    //参数类型是Array的时候，dappper会自动将其转化
    return connection.Query<Person>(sql, new { ids = Ids, }).ToList();
　　}
}