I have a problem with changing a data type from Plain text to number. I need to have a sum of hours spent but because when the database was built Hours Spent column was put as Plain Text instead of as Number. I've tried it in query but I can't convert Plain Text to Number because the Data Type don't match. I also can't alter the database because it is a pretty big company.

Does anybody have a simpler/any way of doing this? I would appreciate your help.