As far as I know there is one type of implementation of LODs. Now referring to the link you have provided, unless I am missing something, LODs are implemented using advanced functionality provided by data sources (DBMS, RDBMS or 100s of others) which is made available by more recent versions of these data sources. In the earlier versions of those, certain features were not available which are used by Tableau to implement LOD expressions successfully. That is why it mentions "For some data sources, only more recent versions support level of detail expressions. Some data sources do not support level of detail expressions at all."
I understood your point, thats the reason i have included the link for reference.
We are using oracle as a datasource and using 10.2 Tableau version which supports the LOD as per the link.
Now my question is how to use LOD Expression at the Datasource Level which is Oracle.
Kumar Mahesh G
Kumar, you are misinterpreting what that means.
"Datasource level" in this context means "does the underlying/root data source (Oracle, SQL Server, Excel, etc.) ALLOW us to use a Level of Detail expression in our workbooks?".
It does not indicate a difference between an LOD in a workbook and an LOD in a datasource.
Does that help?
Kumar, there is only one implementation of LOD and that is within Tableau environment. FIXED LODs are executed much before INCLUDE & EXCLUDE. You can refer to the order of execution of diff. objects in Tableau here
As Micheal has pointed out "Datasource Level" is referring to diff. versions of data sources (Oracle, SQL Server, MS Access, Excel, AWS sources... ). Hope this helps ...
Actually i am confused as per the first statement in the below link.
Level of Detail expressions (also known as LOD expressions) allow you to compute values at the data source level and the visualization level.
Kumar Mahesh Geddam