In some cases (including our unit test environments), these ZSQL methods return wrong value if user-defined variables are initialised with empty string, but they return correct value if initialised with NULL instead.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@24111 20353a03-c40f-0410-a6d1-a30d3c3de9de