Retrieving Distinct Field Values

Description

A common application requirement is to produce a list of unique field values contained in a table or set of records. The SQL language uses the DISTINCT keyword to produce these lists.

Open the SQL Genie and display its Tables tab.

dim qry as C
dim conn as SQL::Connection
conn.open("{A5API=Access,FileName='C:\Program Files\a5v8\MDBFiles\Alphasports.mdb',UserName='Admin'}")
qry = sql_query_builder(conn)

Click Add Table to display the Add Table dialog.
Select "Customer" and click OK. The SQL window now shows:
```
SELECT *
FROM Customer
```
Display the Columns tab.
Click the '<<' button to remove the asterisk "*" from the Selected Columns list.
Select "BILL_STATE_REGION" in the Available Columns list and click the >' button. The SQL window now shows:
```
SELECT [SHIP_STATE_REGION]

FROM Customer
```
Display the Order tab.
Select "BILL_STATE_REGION" in the Available Columns list and click the '>' button. The SQL window now shows:
```
SELECT [BILL_STATE_REGION]
FROM Customer   
ORDER BY [BILL_STATE_REGION]
```
Display the Properties tab.

Select the Distinct? check box. The SQL window now shows:

SELECT DISTINCT [BILL_STATE_REGION]
FROM Customer   
ORDER BY [BILL_STATE_REGION]

Click Execute Query.
Click Close to exit the SQL Genie.
Run the next statements to retrieve and display the data.
```
conn.execute(qry)
sql_resultset_preview(conn.ResultSet)
```
You will see an alphabetized list of unique state values.

Limitations

Desktop applications only.