SQL Server provides an function ISNULL if the value placed in the 2nd parameter if the first parameter passed to the function ISNULL is null.
For example ,
SELECT ISNULL(Designation,’ ‘) from Employee
This will result in the displaying the empty string if the Designation is NULL.
SQL Server’s ISNULL() equivalent in PostgreSQL
The same can be achieved in PostgreSQL using the coalesce function
SELECT coalesce(Designation,' ') from Employee
