[OBIEE11g] Dynamic Variables for Previous Date Period

Best way to quickly work on it is to create variable and use it on dashboard prompt as default to provide first day of last month to current date.
To demonstrate the steps, I have created an excel database to work on the example.
Firstly, create an initialization block and dynamic variables called previous months
Click Manage > Variables to open the Variable Manager.
Click Repository > Initialization Blocks.
Right-click in the white space on the right and select New Initialization Block.

Name the initialization block as Previous_MonthsClick Edit Data Source to open the Repository Variable Init Block Data Source dialog box.  Click the Browse button to open the Select Connection Pool dialog box. Select any connection pool associated with database but not excel sheet. (on the above screen shot, emp is excel database. Double-click the HR > Connection Pool object to add it to the Connection Pool field in the Repository In the Default Initialization String field, type the following SQL

SELECT
ADD_MONTHS(TRUNC(SYSDATE,’MM’),-1),
SYSDATE AS CURRENT_DATE
FROM DUAL




Click OK to close the Repository Variable Init Block Data Source dialog box. The connection pool and initialization string are added to the Repository Variable Init Block dialog box
Click Edit Data Target to open the Repository Variable Init Block Variable Target dialog box.




Use the New button to create TWO variables as FIRST_DAY_LAST_MONTH and create another as CURRENT_DATE
Click OK to close the Repository Variable Init Block Variable Target dialog box. The variables appear in the Variable Target field in the Repository Variable Init Block dialog box




Click Test and verify you get the results in the picture.
Click OK to close the Repository Variable Init Block Data Source dialog box.
Click Action > Close to close the Variable Manager
Check in changes.
Check Global Consistency. If the Consistency Check Manager displays any errors, edit the repository to correct the errors before continuing. If there are no error messages, close the Consistency Check Manager.
Save the repository.
Logon to Answers
You can use these variable anywhere in the reports like on the filters as well as on prompts.
Create any report which provides data by date range
Build the following query
1. Pull the date field with other fields
2. Add filters on the date field




Click on the results, it will pull only data within the date range. This date range will dynamically change every month to provide data from first day of previous month to current date.




You use the variables in the Date Prompt also as below
Similarly, you can you these variables on the prompt as well.
Go to prompt and pull the columns including date column




On the default to section, select server variable and type the variables as




Save the report. The report will filter date with the above date range by default.