archives

In Oracle Database 11g , when you need to update values of certain records from one table,  and the value and the records to update are determined by a second table, you can use a subquery in the update statement to achieve the update. Using “EMPLOYEE”  and “EMPLOYEE_STAGING”  tables as an example , we want […]

In some occasions it is necessary to concatenate data from a number of rows into a single row. Using HR.DEMO table as an example , we want to retrieve a list of employees for each department. Base Data :   Desired Output :