SQL Server on Mac
No, SQL Server will not run on macOS (it can run on Apple hardware, if you use Boot Camp and boot natively to Windows). Otherwise you will need to install virtualization software of some sort, where you install Windows in a VM, and install SQL Server there - I use Parallels Desktop, but there is also VMWare Fusion and Oracle VirtualBox.
(I haven't tested the latter recently, but last time I tried, it was a disaster - gets great reviews as a VM host on Windows, but not very stable on the Mac.)
You can also, of course, RDP to other machines, use SSMS equivalent clients to connect to another SQL Server running on Windows elsewhere, or install a different platform on the Mac (such as PostgreSQL). There is also an IDE from JetBrains called DataGrip and I'm sure others I don't know about.
With SQL Server 2017, you can run SQL Server on Linux, and can even host your own docker container without using Windows at all (I am doing this on my Macs right now - and I wrote about it here).
VS Code, Visual Studio, and Azure Data Studio now run natively on the Mac, so that can work for you too in some scenarios. It all depends on whether you expect SQL Server to actually run on macOS, or if you just want to do most of your work there.
EDIT
Recently SQL Server was released for linux. This makes using Docker a viable solution to "running sql server on mac". You can find some details on how to do this here: https://docs.microsoft.com/en-us/sql/linux/sql-server-linux-setup-docker.
Old answer
If you have a mac and do not want to run a virtual machine, there are a few options.
You can grab a Azure trial and setup an SQL Server instance. Azure also provides a web based query interface.
You could also setup a Amazon RDS free account and create an SQL Server instance.
If you need an MSSQL database client which runs on OS X (similar to SSMS) there are a few available.
- SQLPro for MSSQL (also available on the mac app store) [Note: I am the developer of this app].
- RazorSQL
- Navicat for MSSQL
- TablePlus
You can find a review of multiple clients here.