To omit records that contain duplicate data in the selected columns, use the DISTINCT keyword. To be included in the results of the query, the values for each column or combination of columns listed in the SELECT statement must be unique. For example, several employees listed in an Employees table may have the same last name. If two records contain Smith in the LastName field, the following SQL statement returns only one of the records:
SELECT DISTINCT LastName
FROM Employees
If you omit DISTINCT, this query returns both Smith records.
The output Recordset of a DISTINCT query is not updateable and does not reflect subsequent changes made by other users.