Jump to content

Recommended Posts

Here's what I'm trying to do. I have a database tracking the value of something, and I have 1 record per day. Each record in the table holds the current value, and the average of the last 30 days, and of course, a time stamp.

 

What I want to know is how long has the current trend been over/under the average.

 

Is there an easy way to ask this of mysql? Or would I need to add another column, and have a program manually walk through all the data to fill that column in?

Well, I figured it out myself... :)

 

select ((select ts from item where price>avg30-1 order by ts desc limit 1)-(select ts from item where price<avg30+1 order by ts desc limit 1))/(24*60*60);

 

If the result is positive, it is the number of days it has been over avg30.

If the result is negative, it is the number of days it has been under avg30 (* -1)

If the result is 0, the price is equal to avg30...

 

I hope this helps someone... Btw, ts is a unix timestamp... :)

-YB

This thread is more than a year old. Please don't revive it unless you have something important to add.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.