Hi again,
If I understand correctly, you're after the set of possible values for a tag, rather than the specific value of a tag in one element.
If so, you probably can't get that through SQL.
Tagged value type definitions can be created in-project (Configure - Reference Data - UML Types), in which case they're stored in t_propertytypes. But they can also be located in MDG Technologies, which are XML files the client reads and keeps in memory. Definitions found there are not written to any table.
All Sparx-supplied technologies (such as BPMN) are located in the install directory, eg C:\Program Files (x86)\Sparx Systems\EA, under the sub-directory MDGTechnologies. You can look in there for the tagged value definitions, the format's reasonably readable.
Note also that not all tagged value types have enumerable values. They can be free-text, or references to model elements (known as "RefGUID" tags), or any one of a couple of dozen other types.
HTH,
/Uffe