$ sudo apt-get update
$ sudo apt-get install haskell-hdbc-postgresql-doc

haskell-hdbc-postgresql-doc is installed in your system.

Make ensure the haskell-hdbc-postgresql-doc package were installed using the commands given below,

$ sudo dpkg-query -l | grep haskell-hdbc-postgresql-doc*

You will get with haskell-hdbc-postgresql-doc package name, version, architecture and description in a table

haskell-hdbc-postgresql-doc package basic information: