问题
I have connected Tableau to an MS-Access backend as my datasource.
One of my tables has testing categories (1-19) and the other table has the actual tests done by different supervisors. Each test that the supervisor completes is assigned a category. I need to show a count of how many tests in each category each supervisor has completed in a given month.
I am able to show the count if the supervisor completed a test in a category, the problem I am having is when the supervisor has not completed any test, tableau is not showing the category at all. I need tableau to show the category and a count of 0.
It is showing some categories with a zero count, I believe this is because this supervisor has completed a test in this category during a previous month.
I have tried all different type of join with no luck.
I do not believe that access allows a full outer join.
Screenshot for one supervisor for the month of April (not all categories are showing).
Desired results-Screenshot for one supervisor for the month of April (with all categories showing).
Here is my datasource
SPARTN_Livefeed contains the test information. Supervisor that completed the test, the test number they did and the date.
R_TestCatalog contains a list of all the test numbers and the category id each test belongs to.
R_TestCategory contains all the categories and the test numbers that belong to each category.
sample data
SPARTN_Livefeed
Sheet_ID Supervisor_ID Test Number Date
OB-111 1111 101 01/01/2020
OB-112 1111 401 03/01/2020
OB-113 1111 201 01/01/2020
OB-114 2222 201 01/01/2020
OB-115 2222 201 01/21/2020
R_TestCatalog
test number category id
101 1
201 2
301 2
401 8
R_TestCategory
category id catagory description
1 Signals
2 Restricted Speed
3 Equip Securement
etc, etc ...
回答1:
You'll need a table of all possible combinations of Category and Supervisor. You should be able to create this with a cross join in access. Then left join that cross-joined table (or query) to your test date. That will give a record for all categories and supervisors, even when there hasn't been a test.
来源：https://stackoverflow.com/questions/63195144/tableau-ms-access-not-returning-correct-count