Why this statement invalid: `VALUES ( CURRENT PACKAGESET )`?
I dont think CURRENT PACKAGESET is a special register in LUW 10.5. The special registers can be found at:

https://www-01.ibm.com/support/knowledgecenter/SSEPGG_10.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0008404.html?cp=SSEPGG_10.5.0%2F2-12-2-5

SET CURRENT PACKAGESET is a statement that can only be embedded in an application program:

https://www-01.ibm.com/support/knowledgecenter/SSEPGG_10.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0001005.html?cp=SSEPGG_10.5.0%2F2-12-7-219&amp;lang=en