当不同表中的两列具有相同名称时，如何使用SqlDataReader读取数据？

Question

I have two columns named 'Name' in two different tables. One is in the Store table the other is in the Product table. How do I differentiate which one is read?

The data is taken from 4 different tables using left joins as shown in the query below.

var conn = new SqlConnection("serverinfo");
SqlCommand query = new SqlCommand("SELECT Store.StoreID, Store.Name, 
Product.Name, " +
" StockRequest.Quantity, StoreInventory.StockLevel from Store" +
" LEFT JOIN StoreInventory ON StoreInventory.StoreID = Store.StoreID" 
+ " LEFT JOIN Product ON StoreInventory.ProductID = 
Product.ProductID" + " LEFT JOIN StockRequest ON StockRequest.StoreID 
= Store.StoreID", conn);

SqlDataReader read;

        try {
            conn.Open();
            read = query.ExecuteReader();
            while (read.Read()) {
                Console.WriteLine("{0} {1} {2} {3} {4}",
                                  read["StoreID"],
                                  read["Name"],
                                  read["Name"],
                                  read["Quantity"],
                                  read["StockLevel"]);

            }
            conn.Close();
            } catch (Exception e) {}

The table names are Store, Product, StockRequest, StoreInventory.

Right now the data for both of the 'Name' columns are taken from the Store table. I am unable to take the 'Name' data from the Product table.

Answer 1

You could use alias to give a different name to the duplicate column.

SqlCommand query = new SqlCommand("SELECT Store.StoreID, 
"Store.Name as StoreName," + 
"Product.Name as ProductName," +
" StockRequest.Quantity, StoreInventory.StockLevel from Store" +
" LEFT JOIN StoreInventory ON StoreInventory.StoreID = Store.StoreID" 
+ " LEFT JOIN Product ON StoreInventory.ProductID = 
Product.ProductID" + " LEFT JOIN StockRequest ON StockRequest.StoreID 
= Store.StoreID", conn);

Then just use the right name when reading it, like:

read["StoreID"],
read["StoreName"], read["ProductName"],
read["Quantity"], read["StockLevel"]