About

A dummy table is a virtual table where you can perform a select even if it does't exist.

In oracle, the name of this table is “dual” and you use it for several reasons. The most common is :

• to test some function for instance a regular expression :

select REGEXP_INSTR(' 2343  LM  ', '^([[:blank:]]*[0-9]{4}[[:blank:]]*[A-Z]{2}[[:blank:]]*)$') from dual

You don't need any table as you give the data.

• to handle data. The example below will return always two rows : Month and Quarter.

SELECT 'MONTH' AS REPORT_LEVEL FROM DUAL
UNION
SELECT 'QUARTER' AS REPORT_LEVEL FROM DUAL

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Steps to perform

• In the physical layer, right click on a physical schema and choose New Physical Table
• select “Select” as Table Type from the drop down menu
• and enter the Sql below

Second, you need to create the column report_level from the sql statement.

• click on the column tab and create it