Rowid problem

Hello there, I've encountered a problem concerning rowid's in Informix-SQL 4.10: When executing a join for two tables, say company and country, SELECT company.rowid, company.name, country.name FROM company, country WHERE company.cntrcode = country.cntrcode AND company.compnr IN (SELECT UNIQUE compnr FROM project), I don't get the rowid's from the company-table, but from some temporary table, created by SQL in the process probably. When I start the WHERE -clause with "WHERE 1=1 AND ..." however, I get the RIGHT rowid's. But, to make it even more confusing, when I place the 1=1 part at the end of the WHERE -clause, it doesn't work. Alternatively, when I leave out the sub SELECT condition (companies with existing projects), I also get the RIGHT rowid's. What I want to know is: What difference could the 1=1 part possibly make, has anybody experienced a similar problem and are there any solutions? Thanks in advance,