MySQL date_add
Here's a quick MySQL tip I wanted to throw your way. I created an event system a while back and one of the requirements of the system was to show events that happened yesterday forward, meaning events older than 2 days were to be hidden. MySQL's date_add will allow you to do just that:
The MySQL Example
SELECT title, venue, url, city, state, DATE_FORMAT(date_starts,\'%b %e\') as formatted_date
FROM events
WHERE date_starts >= DATE_ADD(NOW(), INTERVAL -1 DAY) // yesterday!
ORDER BY date_starts ASC
Note that I'm using a negative date value. You can use a positive date value to get tomorrow, next week, next month, etc..
I like the idea of showing events the from past few days -- they show that there's been action recently. Click here for more about MySQL date_add.
![Serving Fonts from CDN]()
For maximum performance, we all know we must put our assets on CDN (another domain). Along with those assets are custom web fonts. Unfortunately custom web fonts via CDN (or any cross-domain font request) don't work in Firefox or Internet Explorer (correctly so, by spec) though...
![Create Spinning Rays with CSS3: Revisited]()
![Image Data URIs with PHP]()
If you troll page markup like me, you've no doubt seen the use of data URI's within image src attributes. Instead of providing a traditional address to the image, the image file data is base64-encoded and stuffed within the src attribute. Doing so saves...
![Ana Tudor’s Favorite CodePen Demos]()
Cocoon
I love canvas, I love interactive demos and I don't think I have ever been more impressed by somebody's work than when I discovered what Tiffany Rayside has created on CodePen. So I had to start off with one of her interactive canvas pens, even though...
Or you can do it like this: date_starts >= NOW() – INTERVAL 1 DAY
Easier to read in my opinion :) Good tip! I do it like this quite often
I prefer using php function strtotime() because queries using MySQL functions like NOW() can’t be cached
@macol: Ohhhh, good tip!
Hmm good tip indeed, but… The queries still cannot be cached if you use something as dynamic as strtotime(‘now’), isn’t that right?
So using strtotime() does not enable the query to be cached? Or am I wrong?
strtotime() would only give you an advantage if the same query is run during the same second?
If you want caching to work, you can truncate the time part like this:
Then it’ll be good for the whole day. This has the added benefit of matching the logical meaning of “yesterday” rather than being precicely 24 hours ago.
@Jeremy Parrish: Why didnt I think of this? :) Thanks!
This query will not be used index.
@Niklas Berglund: your query must be deterministic – query might provide same result no matter how many times it is run, if data remains the same. So if your query uses non-deterministic functions such as NOW(), UUID(), RAND(), CONNECTION_ID() etc it will not be cached.
However, if you pass in a fixed value from PHP as in
SELECT * FROM logs WHERE logstamp = ”
it will be cached.
(the php function today() is just a one-liner that returns the current day in mysql format)
@Metric Stormtrooper: SELECT * FROM logs WHERE logstamp = ‘::php today() ::’
hm, cant post php syntax here, but you get the idea
Or you can use this: DATE_SUB(NOW(), INTERVAL 1 DAY)