ACC: Adding a Parameter to a Union Query

MORE INFORMATION

The Customers and Suppliers By City union query selects records from both the Customers and Suppliers tables. The SQL of this query is as follows:

   SELECT City, CompanyName, ContactName, "Customers" AS [Relationship]
   FROM Customers
   UNION SELECT City, CompanyName, ContactName, "Suppliers"
   FROM Suppliers
   ORDER BY City, CompanyName;
				

The SQL of Union Query in Microsoft Access 2.0 is as follows:

   SELECT [Company Name], [City]
   FROM [Suppliers]
   WHERE Country = "Brazil"
   UNION SELECT [Company Name], [City]
   FROM [Customers]
   WHERE Country = "Brazil";
				

To add a parameter to the union query, you must duplicate the parameter in each SELECT clause in the query. To add a parameter (in this case a city) to the query, follow these steps.

CAUTION: Following the steps in this example will modify the sample database Northwind.mdb (or NWIND.MDB in version 2.0). You may want to back up the Northwind.mdb file, or perform these steps on a copy of the Northwind database.

1. Open the sample database Northwind.mdb (or NWIND.MDB in version 2.0).
2. Open the Customers and Suppliers By City query (or Union Query in Microsoft Access 2.0) in Design view.
3. Change the query's SQL so that it looks like the following:
   
   In Microsoft Access 7.0 and 97:
   

         SELECT City, CompanyName, ContactName, "Customers" AS [Relationship]
         FROM Customers
         WHERE Country = "Brazil" and City = [Enter City]
         UNION SELECT City, CompanyName, ContactName, "Suppliers"
         FROM Suppliers
         WHERE Country = "Brazil" and City = [Enter City]
         ORDER BY City, CompanyName;
   						

   
   In Microsoft Access 2.0:
   

         SELECT [Company Name], [City]
         FROM [Suppliers]
         WHERE Country = "Brazil" and City = [Enter City]
         UNION SELECT [Company Name], [City]
         FROM [Customers]
         WHERE Country = "Brazil" and City = [Enter City];
   						

   
   
4. Save the query and close it.
5. Open the query in Datasheet view and type Rio de Janeiro in the Enter City dialog box. Note that only the Customers and Suppliers from Rio de Janeiro are displayed.