How to access the Postgres SQL from k8s environment

Hi Team,
I have deployed Kong Gateway + Postgres in k8s environment (connecting to cluster via config file via windows platform )using config file(Yaml) and sample proxy is working fine.
I tried to access the Postgres SQL various ways but no luck here , Please help!!

Ref links:-
https://docs.vmware.com/en/VMware-Tanzu-SQL-with-Postgres-for-Kubernetes/1.5/tanzu-postgres-k8s/GUID-accessing.html

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  1. ./kubectl exec -it postgres-0 -n kong-postgres – psql

Unable to use a TTY - input is not a terminal or the right kind of file

psql: FATAL: role “root” does not exist
command terminated with exit code 2

  1. ./kubectl exec -it postgres-0 -n kong-postgres – /bin/sh
    ./kubectl exec postgres-0 -n kong-postgres – /bin/sh
    ./kubectl exec -it -n kong-postgres postgres-0 bash
    ./kubectl exec postgres-0 -n kong-postgres --/bin/sh --kubeconfig config

Unable to use a TTY - input is not a terminal or the right kind of file
error: Internal error occurred: error executing command in container: failed to exec in container: failed to start exec “e8a4f10651699bc1c8279ee32327fa5ca29337f2627ab0eea47c3e122947598d”: OCI runtime exec failed: exec failed: container_linux.go:380: starting container process caused: exec: “C:/Program Files/Git/usr/bin/bash”: stat C:/Program Files/Git/usr/bin/bash: no such file or directory: unknown

  1. Unable to connect from power shell too.