SSD means Solid State Drive - as such is does not spin, thus the RPM is 0!
The same applies to flash memory.
That is why their read/write rates are superior to spinning disks, even where they use the same interface, e.g. SATA 3. Modern interfaces allow far higher data transfer rates than any available spinning dsisk can manage - hence the demise of the WD Raptor series.
SATA and SAS spinning disk drives have various rated RPM - you should check the specification of any you are considering.
Allen is right on, here is a quick course in Storage 101 for video editing.
RPM = Revolutions Per Minute.
The speed specification of SSD's used for video editing is the Sequential Read/Write Rate For instance here is a typical SATA III SSD
Here is a very good M.2 PCIe Gen 3 x4 SSD:
And here is the sequential read performance on lousy 7200 RPM 1 TB hard disk drive. Notice that as a hard disk drive fills up th read speed falloff significantly.