Change Column data type on a BIG table

Hi there, The table has about 50 million records. The data type of one of the columns currently is DECIMAL(13,2). We want to change it to DECIMAL(9,2). What we did was: Alter table TabA modify colA(9,2) And it took forever (the server is running in no-log mode). Is there any other better/faster way? Another question about SQL in Informix In Sybase I can do this: select 'abc..... ' With Oracle I can do similar as: select 'abc......' from dual Can/how I do it on Informix? Thanks in advance for your help. Tung Nguyen