Select is failing

Hi,

See the below select statement. It is failing. I think this is because of domain types in CDHDR and EKKO. How should trouble shoot this..

SELECT OBJECTID

USERNAME

UDATE FROM CDHDR INTO TABLE GT_HDR

FOR ALL ENTRIES IN GT_EKKO WHERE

OBJECTID IN GT_EKKO-EBELN AND

USERNAME IN SO_ERNAM AND

UDATE IN SO_ERDAT.

Thanks

Reddy.