It should take an average learner about two to three weeks to master the basic concepts of SQL and start working with SQL databases.
But in order to start using them effectively in real-world scenarios, you'll need to become quite fluent; and that takes time.
To become an SQL Server DBA, you need to complete training courses on and using Microsoft's Structured Query Language (SQL) Server database.
Most SQL Server DBAs have a bachelor's degree in computer science or a related field of information technology.