I have a table for e.g.

```
Merchant(
    id (PK,char(15),not null),
    name (varchar(22),null),
    city(varchar(10),null),
    location(varchar(10),null),
    state_code(int,null),
    country_code(int,null)
)

```

Where `city` is always `NULL` and `name` is also `NULL`.

Someone updated these fields as the *string* `"NULL"`.

How can I find the difference?