https://adamdrake.com/command-line-tools-can-be-235x-faster-...

  PSQL="psql postgresql://$POSTGRES_USER:$POSTGRES_PASSWORD@$DATABASE_HOST:$DATABASE_PORT/$POSTGRES_DB -t -P pager=off -c "
  
  OLD="CURRENT_DATE - INTERVAL '5 years'"

  $PSQL "SELECT id from apt WHERE apt.created_on > $OLD order by apt.created_on asc;" | while 
  read -r id; do
    if [[ $id != "" ]]; then
      printf "\n\*\* Do something in the loop with id where newer than \"$OLD\" \*\*\*\n"
      # ...
    fi
  done

I don't do much sql in bash scripts but I do keep some wrapper scripts that let me run queries from stdin to databases in my environment