CODEWITHSUNDEEP
ms-access
Mark
Mark

Reputation: 43

MS-Access show only items that meet multiple criteria

I am new to Access and I am looking for a solution that is beyond the ability of the others in my company and may be beyond what access can do.

I have the following fields.

Date:  Last Name:  First Name:  Test1:  Test2:  Test3:

I am looking for the following to happen.

Thank You,

Upvotes: 0

Views: 796

Answers (1)

Olivier Jacot-Descombes
Olivier Jacot-Descombes

Reputation: 112362

First, you need a primary key column in order to be able to easily and unambiguously identify each record. In Access this is easily achievable with a Autonumber column. Also, in the table designer, click the key symbol for this column. This creates a primary key index. A primary key is a must for every table.

Let us call this column TestID and let's assume that the table is named tblTest.

The problem is that your condition refers to several records; however, SQL expects a WHERE clause that specifies the conditions for each single record. So let’s try to reformulate the conditions:

  • Keep the record with the most passes for each user.
  • Keep records with "NotUsed" in any test field.

The first condition can be achieved like this:

SELECT First(TestID)
FROM
    (SELECT TestID, [Last Name], [First Name] FROM tblTest
     ORDER BY IIf(Test1='pass',1,0) + IIf(Test2='pass',1,0) + IIf(Test3='pass',1,0) DESC)
GROUP BY [Last Name], [First Name]

This gives you the TestID for each user with the most passes. Now, this is not the final result yet, but you can use this query as a subquery in the final query

SELECT * FROM tblTest
WHERE
    Test1='NotUsed' OR Test2='NotUsed' OR Test3='NotUsed' OR
    TestID IN ( <place the first query here...> )

Is this what you had in mind?

Another thought is about normalization. Your table is not normalized. You are using your table like an Excel sheet. As your database grows you'll get more and more into trouble.

You have two kinds of non-normalization.

One relates to the fact that each user's first name and last name might occur in several records. If, in future, you want to add more columns, like user address and phone number, then you will have to repeat these entries for each user record. It will become increasingly difficult to keep this information synchronized over all the records. The way to go is to have at least two tables: a user table and a test table where the user table has a UserID as primary key and the test table has this UserID as foreign key. Now a user can have many test records but still always has only one unique user record.

The other one (non-normalization) occurs because you have 3 Test fields in a single record. This is less of a problem if your tests always have the same structure and always require 3 tests per date, but even here you have to fall back to the "NotUsed" entries. There are several ways to normalize this, because a database can have different degrees of normalization. The tree ways:

  • Only one test table with the fields: TestID (PK), UserID (FK), Date, Result, TestNumber.
  • A test day table with the fields: TestDayID (PK), UserID (FK), Date + a test result table with the fields: TestResultID (PK), TestDayID (FK), Result, TestNumber
  • Then you can combine the two previous with this addition: Instead of having a TestNumber field, introduce a lookup table containing information on test types with the fields: TestTypeID (PK), TestNo, Description and in the other tables replace the column TestNumber with a column TestTypeID (FK).

See: How to normalize a table using Access - Part 1 of 4 or look at many other articles on this subject.

Upvotes: 1

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