Hey JB,
I had a quick look into the function module and found that three tables are involved here:
STXH - text headers
STXL - text lines (for SAPScript texts)
STXB - text lines (for non-SAPScript texts)
Unfortunately, the access to the data is rather complex and does use the ABAP table cluster interface.
That means, that just as for pool/cluster tables, the text information are stored in a encoded binary format that cannot be processed directly by SQL.
This format can also be compressed, making it even more difficult to access the data from SQL.
Sorry, but I don't know of any way to directly use this data on DB level.
You may need to export the data to a plain table so that it could be read from there.
- Lars