SQL SERVER函數

SQL SERVER中函數以及函數的調用

一、建立有返回值的函數

函數：

CREATE Function GetCount(@typeid int)
returns int
as
begin
declare @result int
select @result=sum(ID) from books where TypeID=@typeid
if (@result is null)
set @result=0
return @result
end

調用示例：

SqlConnection conn = new SqlConnection("Server=.\\SQLEXPRESS;Initial Catalog=Test;Integrated Security=true");
            conn.Open();

            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.CommandText = "GetCount";
            SqlParameter sp = new SqlParameter("@typeid", SqlDbType.Int, 2);
            sp.Direction = ParameterDirection.Input;
            sp.Value = 1;
            cmd.Parameters.Add(sp);
            sp = new SqlParameter("@returnvalue", SqlDbType.Int, 4);
            sp.Direction = ParameterDirection.ReturnValue;
            cmd.Parameters.Add(sp);
            cmd.ExecuteNonQuery();
            Response.Write(cmd.Parameters["@returnvalue"].Value.ToString());

二、建立返回表的函數

函數：

Create function GetTable(@typeid int)
returns table
as
return(select * from books where TypeID=@typeid)

調用示例：

    SqlConnection conn = new SqlConnection("Server=.\\SQLEXPRESS;Initial Catalog=Test;Integrated Security=true");
            conn.Open();

            SqlCommand cmd = new SqlCommand();             cmd.Connection = conn;             cmd.CommandType = CommandType.Text ;             cmd.CommandText = "select * from GetTable(@typeid)";//表值函數的調用             SqlParameter sp = new SqlParameter("@typeid", SqlDbType.Int, 2);             sp.Direction = ParameterDirection.Input;             sp.Value = 1;             cmd.Parameters.Add(sp);             SqlDataAdapter da = new SqlDataAdapter(cmd);             DataTable dt = new DataTable();             da.Fill(dt);             GridView1.DataSource = dt;             GridView1.DataBind();