When you create a field in an MS Access table you can create a validation rule for it. The rule might for example restrict entry to numeric values in a range or dates in a range. Sometimes you want the rule to refer to a value in another field. For example in our employees table we have a Date Hired field and a Review field. The review date has to be more than 60 days after the date hired date. So the rule would be [Yearly review]>=[Date Hired]+60
If I enter this rule into the validation rule property and then save the table I get this error: Invalid SQL syntax – cannot use multiple columns in a column-level CHECK constraint. This basically tells you you cannot refer to another field in your validation rule.
To achieve this you will need to enter the rule in the table’s property sheet. Open the property sheet and you will find a validation rule and a validation text property for the table: enter your rule there.