yum repolist
Run these as the root user.
cd /tmp/
wget https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/getPackage/oracle-epel-release-el7-1.0-4.el7.x86_64.rpm
yum install -y oracle-epel-release-el7-1.0-4.el7.x86_64.rpm
Development Tools by Oracleyum groupinstall 'Development Tools'
Run this as the root user.
yum install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm
This will add repository for PostgreSQL 12 to PostgreSQL 15.