使用C＃中的内部连接语句将nvarchar值转换为数据类型int时，转换失败

Question

Error Description

myCon = new SqlConnection(@"myconnectionstring");
myCon.Open();

string id_trender = "UPDATE b SET b.id_trender = @a.id_trender FROM trenders a JOIN adjustments b ON a.dim_name_trender = b.name";
//var cmd1 = new SqlCommand(id_trender, myCon);

cmd1 = new SqlCommand("INSERT INTO adjustments(id_trender) VALUES" + "(@id_trender)", myCon);
// cmd1.Parameters.AddWithValue("@id_trender", SqlDbType.Int).Value = id_trender;
cmd1.Parameters.Add(new SqlParameter("@id_trender", id_trender));

cmd1.ExecuteNonQuery();
myCon.Close();

I get this error when making a connection to my database in SQL Server Management Studio.

I have a two tables with id_trender in one table and I'm using an inner join to insert the id_trender into another table. Basically, I want to match the id on trender table to the name in adjustments table.

Here is my table structure in SQL:

Adjustments table:

id, name, id_trender

Trenders table:

dim_name_trender, id_trender

Answer 1

解决方法是只拥有update语句，因为我已经连接到服务器：string id_trender =“ update b set b.id_trender = a.id_trender FROM Trenders a JOIN Adjustments b ON a.dim_name_trender = b.name”;

Answer 2

尝试这个：

cmd1 = new SqlCommand("INSERT INTO adjustments(id_trender) VALUES @id_trender)", myCon);