'How can I make a MySQL SUM query return zero instead of null if there are no records?

Here is my select query:

SELECT SUM(rating) AS this_week 
FROM table_name 
WHERE UNIX_TIMESTAMP(created_at) >= UNIX_TIMESTAMP() - 604800)

Which basically counts the rating of an item for the last week (604800 is a number of seconds in 1 week).

The problem is that when there are no rows in the table, the this_week will be returned as NULL. I would like the query to return 0 in case there are no rows in the table. How to do it?

sqlmysql


Solution 1:[1]

Can't you use IFNULL(SUM(rating), 0)?

Solution 2:[2]

Try this one : SUM(IFNULL(rating, 0))

Sources

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Source: Stack Overflow

Solution Source
Solution 1 TheKojuEffect
Solution 2 Kai - Kazuya Ito

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