how to use distinct in ms access

Question

I have two tables. Task and Categories.

Answer 1

Okay.Its working this way.

SELECT DISTINCT Task.Priority, Task.Subject, Task.Status, Task.DueDate, 
Task.Completed, Categories.Category
FROM Task, Categories
WHERE (((Categories.CategoryID)=[Task].[CategoryID]));

Answer 2

I don't like using SELECT DISTINCT, I have found that it makes my code take longer to compile. The other way I do it is by using GROUP BY.

    SELECT Priority, Subject, Status, DueDate, Completed, Category
    FROM Task, Categories
    WHERE Categories.CategoryID=Task.CategoryID
    GROUP BY Subject;

I do not have VBA up at the moment but this should work as well.

Answer 3

Using SELECT DISTINCT will work for you, but a better solution here would be to change your database design.

Duplicate records may lead to inconsistent data. For example, imagine having two different status in different records with the same TaskID. Which one would be right?

A better design would include something like a Task table, a Contact table and an Assignment table, as follows (the fields in brackets are the PK):

Tasks: [TaskID], TaskPriority, Subject, Status, DueDate, Completed, StartDate, Owner, CategoryID, ContactID, ...

Contact: [ID], Name, Surname, Address, PhoneNumber, ...

Assignment: [TaskID, ContactID]

Then, you can retrieve the Tasks with a simple SELECT from the Tasks tables. And whenever you need to know the contacts assigned to a Tasks, you would do so using the JOIN clause, like this

SELECT T.*, C.*
FROM TaskID as T 
  INNER JOIN Assignment as A
    ON T.TaskID = A.TaskID
  INNER JOIN Contac as C
    ON A.ContactID = C.ID

Or similar. You can filter, sort or group the results using all of SQL's query power.