You will have to create a new role or change an existing role and assigned the role to the user.
Go to Tools → Security → Roles to create a new role. Press the Role bottom and then Permissions to assign permissions to the role. Select “Table Data” in , your table number in and clear the defaulted “Yes” in , and leaving only = “Yes” and = “Yes”.
As described above or do you mean why?
If why; then because Navision on SQL have problems with empty (not used) tables. The users might get permissions errors if you don’t assign permissions to these empty tables…