---

- hosts: Test_Hosts
  sudo: yes
  sudo_user: root
  gather_facts: yes
  tasks:
  - name: Login to DB and run command
    shell: export PGPASSWORD='Password'; psql -U 'user' -d 'db' -c 'select * FROM table';
    register: select_all_from_table

  - name: Display table contents
    debug: msg="{{ select_all_from_table.stdout }}"

- name: Login to DB and run command
    shell: export PGPASSWORD='Password'; psql -U 'user' -d 'db' -c 'select * FROM table';
    register: select_all_from_table
    environment:
      PGPASSWORD: '{{ pgpassword }}'

- name: set passwd file for PSQL
  copy:
    src: files/pgpass
    dest: ~/.pgpass
    mode: 0600           ### important: will not work with wrong permissions

- name: PSQL command
  shell: "psql -U 'user' -d 'db' -c 'select * FROM table'"
  register: select_all_from_table

hostname:port:database:username:password

*:*:db1:user1:passwd1
*:*:db2:user2:passwd2