update file_information set languageid=1 where languageid is NULLStruggled a bit to get the syntax right, with languageid ='', languageid = NULL , NOT (languageid>0 and languageid<9) and so on, till I googled the correct syntax for NULL.
One more snippet of SQL Gyaan is that to insert, update etc for fields with type interval / timestamp , the syntax is
UPDATE "file_information" SET "duration" = interval '00:01:09' where file_id = 2020and so on. One has to do a sort of typecasting using the keyword interval. One can even say interval '1 hour' and so on. From http://www.linuxjournal.com/article/9618