In my previous article I’ve shown how to get rank using mysql query. Now I’m showing how to retrieve result based on today, week and month using mysql query. Actually I also implemented this in my quiz project so I’m sharing this with you.

For the table structure please look my previous article http://thinkdiff.net/mysql/how-to-get-rank-using-mysql-query/

Task 1: I’ve to retrieve those users rank who played the game today.
Solution: Look at the query

SELECT uid, participated, correct, wrong from quiz_user
    WHERE DAYOFMONTH(CURDATE())=extract(day from updated)
    ORDER BY correct DESC, participated ASC
    limit 30

So the above query returns the result of those users who played today. Here

CURDATE() …

First of all, I'd like to thank everyone who read and gave their 2 cents about the [WordPress Plugin Development] How To Include CSS and JavaScript Conditionally And Only When Needed By The Posts post. The article was well received and will hopefully spark some optimizations around loading styles and scripts.

Here are some discussions and mentions around the web:

• an article on Weblog Tools Collection
• a forum post on WP Tavern
• …

I don't feel like it to change my patches with every new release of PHP. In order to give something back to the community and to support my laziness, I publish a few patches for the PHP language. Some are really useful, some are quite okay and others are only to help in a more particular case. But read over the new featureset to make you an own opinion.

Read the rest »

This article shows how to create a MySQL-plugin that can be used to create a function which can in turn be used in stored procedures. The function will produce an integer value representing the time (to the nearest usec).

I’m working on an article for conflict detection/resolution when using MySQL Cluster asynchronous replication which requires an integer column to store a timestamp for comparison purposes. In fact, it doesn’t actually need the timestamp to represent an absolute or even a relative point in time – all it cares about is that the if the function is called twice on 2 different hosts that the 2nd call will always result in a larger number than the 1st. Obviously, in a production environment the times on the 2 hosts would need to be kept in sync.

The c code (inttime.c)

#include <mysql.h>
#include <sys/time.h>

my_bool inttime_init(UDF_INIT *initid,UDF_ARGS *args, char *message) {
  return 0;
} …

Background Knowledge

I’m trying to determine the difference in minutes between two timestamps. I’m using Pear::Date to do this. The issue comes into play when I noticed that the wrong timezone was being used by Pear::Date, UTC. If I do not use Pear::Date the timezone is set correctly.

I have tried using date_default_timezone_set() and it does set the timezone back, however I feel this shouldn’t be necessary as the default timezone should be used. I have been using date_default_timezone_get() to determine what timezone is being used.

It’s my understanding that Pear::Date uses UTC when it is unable to determine the default timezone. As far as I know I have the default timezone set correctly and with a …

This is a post about SYSDATE() and NOW() and CURRENT_TIMESTAMP() functions in MySQL.

Firstly, note is that of these three, only CURRENT_TIMESTAMP() is part of the SQL Standard. NOW() happens to be an alias for CURRENT_TIMESTAMP() in MySQL.

Secondly, note that replication does not work well with non-deterministic functions. And “hey, what time is it?” is non-deterministic. Ask it twice, with a second apart between asking, and both times you get different results (with at least second precision).

You can start to see the problem here….but there’s more…. (more…)

Background Knowledge

Since MySQL v4.1 timestamp and datetime data types are formatted “YYYY-MM-DD HH:MM:SS”. Prior to MySQL v4.1 the timestamp was formatted as YYYYMMDDHHMMSS” and datetime formatted as “YYYY-MM-DD HH:MM:SS”. Refer to MySQL Reference Manual for further details.

The Unix timestamp differs from MySQL. Unix’s timestamp is a integer value of seconds since January 1, 1970. For further explanation of Unix timestamps refer to Wikiepedia or UnixTimestamp.com.

Solutions

In MySQL you can use Unix_Timestamp() function.

Query Example: SELECT …