I am trying to print a string answer to a question, on whether a specific item was bought today. I want the end result to look something like this:

```
| was_the_item_bought  | 
| -------------------- | 
| "no one bought this" | 

```

However I keep getting null / no rows displayed. 

```
| was_the_item_bought  | 
| -------------------- | 

```

Here's the simplified query.

```
#StandardSQL

with store_list AS (
select item 
from store
),

bought_today AS (
select item 
from register 
where item = 'apple' # <--- only one item will be listed here
)

select (case when b.item is NULL 
    then "no one bought this" 
    else "bought" end) as was_the_item_bought
from store_list a  
left join bought_today b  
on a.item = b.item

```

How can i make it display a string? 

Edit: Updated to specify it's `b.item` instead of `item`.