Question

I have two tables and need to retrieve some columns from both tables based on the common key which is ProductID. I tried the following but got an error "Incorrect syntax near the keyword ‘JOIN’"

string selectProductStatement = 
"SELECT Products.Code, Products.Description,"+
"Products.Category, Products.Price, BookProducts.Author"+
"FROM Products"+
"INNER JOIN BookProducts ON (Products.@ProductID = BookProducts.ProductID)";

SqlCommand comm = new SqlCommand(selectProductStatement, connection);
comm.Parameters.AddWithValue("@productID", productID);

the tables are:

Products

  ProductID
  Code
  Description
  Category
  Price

BookProducts

  BookID PK
  ProductID FK
  Author

Answer 1

Personally I like to use a literal string for SQL commands to get rid of all the concatination all together. Saves time and headaches!

note the @ symbol before defining the string. Also wrapping commands in a ‘using’ brace means you cant forget to dispose of it.

 string selectProductStatement = @"           SELECT 
                                              Products.Code, 
                                              Products.Description,
                                              Products.Category, 
                                              Products.Price, 
                                              BookProducts.Author
                                              FROM Products
                                              INNER JOIN BookProducts 
                                              ON (Products.@ProductID = BookProducts.ProductID) ";
            string connectionString = string.Empty;

            using (SqlConnection sqlConnection = new SqlConnection(connectionString))
            {
                sqlConnection.Open();

                using (SqlCommand sqlCommand = new SqlCommand(selectProductStatement, sqlConnection))
                {
                    sqlCommand.Parameters.AddWithValue("@productID", productID);

                    //Etc
                }
            }