We have been using SQL and we switched to Oracle Essbase. Both programs are operating and depending on the client's needs. We move between both platforms. However, the primary solution is Oracle Essbase. Depending on how we need to provide the solution because they have already something on the Azure server in that case, we need to use Azure servers. Now we have a solution that tackles both the database needs. It is my opinion, it is more comfortable in Oracle rather than a SQL server.

We did previously use a different product. We used PostgreSQL. We wanted an update of features and found that open-source databases don't have the maintenance tools we required. Also, using them was risky in general. 

I've always used the same tools.

We previously used MySQL and switched to Oracle Essbase. It is scalable with many features.