Small to medium size Databases can suitably run in the General purpose VM series A V2, DS V2. DS series support the addition of SSD disks to the VMs typically meant for high IO operations commonly seen in Database servers.
Large relational databases can be run on Compute intensive VM series like the D11-14 V2 series and the G series. These series are suitable for large in-memory operational requirements like Analytics and Data warehousing. Storage optimized L series are suitable for IO intensive, high disk throughput, NoSQL database requirements.