I'm learning SQL for my job and trying to filter orders by date. I ran a query to retrieve orders created in January 2024, but it returns more rows than I anticipated. Here's what I've done so far: I've adjusted the `WHERE` condition, searched for information using the phrase "sql between date inclusive," and removed joins step by step. My simplified query looks like this:
SELECT *
FROM orders
WHERE created_at >= '2024-01-01'
AND created_at <= '2024-01-31';
I expected to see only the data from January, but I'm still encountering some rows from February. Could this be related to how timestamps work that I'm not grasping?
2 Answers
It sounds like a timestamp issue. Your `created_at` column likely stores full datetime values, like `2024-01-31 23:59:59`. When you compare it with `<= '2024-01-31'`, it only checks up to midnight of that day. Try changing your condition to `AND created_at < '2024-02-01'` to include everything right up until the last second of January.
Check the time part of your timestamp. If you’re using `<= '2024-01-31'`, it might include February rows since it's looking at the entire day, not just the date.
That shouldn't be the case, right?
But wouldn't that exclude any rows from January 31st after noon?