In SQL we had clients that requested health checks, we validated installation parameters, indices, the distribution of the installation, for example how were the mdf, in which disks, if they followed the best practices
I need to add that I also handle AZURE issues, specifically backup center and support for SQL server Iaas deployments lacking appropriate extensions to make backups. Additionally, I had to certify myself in several Azure technologies.
Initially I implemented a telephone billing software that was supported by SQL databases, there I learned to use SSMS, in some support cases we evaluated traces, queries, in the administration part we executed tasks such as backups, restores, migrations with massive SSMS, recovery of bases, later they sent me to Teleperformance as an inhouse engineer and I had to learn a little more about administration