I have a column with uncertain birth date information, displayed in one ot the following ways (where 0 means digits 0–9):
UPDATE [test] SET BYEAR = left(BYEAR,LEN(FAAR)-4);
In MS Access, you can keep the first four characters by doing:
UPDATE [test] SET BYEAR = left(BYEAR, 4);
This does not check that the first four characters are actually digits, but it does do what you want for the data you have provided.