mimer (a proprietary database unrelated to informix) has an online sql validator at
http://developer.mimer.se/validator/index.htm -- this will check your sql for valid syntax according to the sql-92 or sql-99 standards
another option is to take your query and add a condition to the WHERE clause that will guarantee no rows returned -- it will still run, but it should run extremely quickly (if the optimizer is doing its job)
change
select foo from bar where conditions
to
select foo from bar where 0=1 and (conditions)
rudy
http://rudy.ca/