Run the following commands:
terraform state rm 'module.postgresql_example.azurerm_postgresql_database.pgsql'
terraform import 'module.postgresql_example.azurerm_postgresql_database.pgsql["psqlservername1"]' '/subscriptions/SUBSCRIPTION_UUID/resourceGroups/psql-dev-rg/providers/Microsoft.DBforPostgreSQL/servers/psqlservername/databases/psqlservername1'
...
terraform import 'module.postgresql_example.azurerm_postgresql_database.pgsql["psqlservername4"]' '/subscriptions/SUBSCRIPTION_UUID/resourceGroups/psql-dev-rg/providers/Microsoft.DBforPostgreSQL/servers/psqlservername/databases/psqlservername4'
Note: These are just values based on the examples/ folder.