Question

I have an application storing the times a restaurant is open:

My code to get the currently open restaurants. My SQL query (simplified) looks like

SELECT * 
  FROM `restaurants` r 
 WHERE r.from <= NOW()  
   AND r.to >= NOW();

The problem here is, there’s an entry which rolls over — it’s for a restaurant open from 11 AM to 3 AM the next day.

What would be a good query to capture that particular restaurant?

Answer 1

In pseudo code:

if (close > open) {
    store_is_open = (open <= now <= close)
} else {
    store_is_open = (open <= now || now <= close)
}

Converting that to SQL:

WHERE IF(
    r.from < r.to,
    NOW() BETWEEN r.from AND r.to,
    NOW() >= r.from OR NOW() <= r.to
)

You might also want to check for places which are open 24 hours. The below code assumes that you would set the from and to times to be the same (eg: from midnight to midnight)

WHERE IF(
    r.from = r.to,
    1,
    IF(
        r.from < r.to,
        NOW() BETWEEN r.from AND r.to,
        NOW() >= r.from OR NOW() <= r.to
    )
)