Question

I have joined the same 2 tables twice using different aliases in a SQL query to enable me to select 2 (potentially but not always) different address ids which then link in to the address table.

SELECT C.court_id, C.court_name, CA.court_address, CA2.court_address...
FROM court C " +
JOIN court_addr CA ON C.court_addr_id = CA.court_addr_id " +
JOIN court_addr CA2 ON C.court_postal_addr_id = CA2.court_addr_id " + ...

Now when trying to output the results of this query using ASP.NET C# I’m unsure how to specify which of the two addresses to Response.Write. Putting the alias in front of the column name (as in the 4th string value below) doesn’t work and brings up an error. Is there a way of differentiating between the two addresses in C# despite them both having the same column name in the database?

while (myDataReader.Read())
{
    string court_id = myDataReader["court_id"].ToString();
    string court_name = myDataReader["court_name"].ToString();
    string court_address = myDataReader["court_address"].ToString();
    string court_postal_address = myDataReader["CA2.court_address"].ToString(); 
    etc.....

Thanking you muchly in advance

Answer 1

You should use an alias in your sql to distinguish them, then you will be able to return the correct value:

SELECT C.court_id, 
  C.court_name, 
  CA.court_address as CACourtAddress, 
  CA2.court_address as CA2CourtAddress
FROM court C " +
JOIN court_addr CA ON C.court_addr_id = CA.court_addr_id " +
JOIN court_addr CA2 ON C.court_postal_addr_id = CA2.court_addr_id " + ...