Hi,
try something like.
CASE
WHEN
@catalog('BPUR_M10_CON10')."PUBLIC"."IBPUR_M10"."BIS_PBLNR__BTSWCHNL" IS NULL
THEN
@catalog('BPUR_M13_CON10')."PUBLIC"."IBPUR_M13"."0PLANT"
WHEN @catalog('BPUR_M13_CON10')."PUBLIC"."IBPUR_M13"."0PLANT"='EHO'
THEN
'CD'
END
Amit