queries now work (except for the missing sum for uchr)
queries now work (except for the missing sum for uchr)

sql.c: fix crash on missing conversion function

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb