How can I connect postgreSQL with native SQL queries

I plan to select the last item by date and time listed in the table.

Table.Buffer() make my refresh time significantly slower.

1. Will it be better if I do it with SQL ?
2. How could I manually enter SQL query since there is no advance option in PostgreSQL connection option.

M code are below :

let
Source = PostgreSQL.Database("xx.xxx.xxx.xx:port", "db-name"),
sc_aaa_vw_aaa_info = Source{[Schema="sc_aaa",Item="vw_aaa_info"]}[Data],
....
in
...