I'm a beginner for php and developing this web application, which users who registered on this site, can be claimed some scores in every one hour. When a user claims at some time, database stores that time as time data type in to user_claim_time column. When that same user tries for his next claim, this php script be able to get his last claim time and add one hour to check if the user really claims in an one hour.
So, my question is how can we add one hour to queried time. I'm using php time(h:i:s) function to store server's current time into the database.
You can do something like this:
SELECT * FROM your_table
WHERE user_claim_time < NOW() - INTERVAL 1 HOUR
However i recommend you to use user_claim_time column in datetime format.
Because time like this '00:00:00' will produce negative output as one hour subtraction can change the date or month as well. For example date like this '2017-08-01 00:00:00'.
So using datetime is the right way i think to properly compare time difference.
Related
I am using CodeIgniter and I am calculating the total time from the dates.
Explanation:
What I am doing is, Every login I am inserting the last_Ativity date and time in the database using below code.
$data_login= array('emp_id' =>$result->id ,'last_activity' =>date("Y-m-d H:i:s", STRTOTIME(date('h:i:sa'))));
$this->db->insert('tbl_current_login',$data_login);
last_activity time continuously updating if the user still in the system . (I am using ajax to update the datetime. I haven't shared that code).
Now I have to calculate the total time of the specific user for a single day(current date).
For example- emp_id 26 logged in twice so I have to calculate the time
First-time login date and time:-2018-09-17 07:27:55
Second-time login date and time:- 2018-09-17 07:35:22
It will increase depending upon how many time the user logged in.
I am confused about the time. Am I on the right path to calculate the total hour login in the system?
Should I use an MYSQL query or PHP to calculate? I need some idea.
Would you help me out in this?
This is what I would do
last_activity time continuously updating if the user still in the system . (I am using ajax to update the datetime. I haven't shared that code).
Before you update the row.
check if a row for activity exists
if it does, get the timestamps for the date and subtract the current time (the one you are changing last_activity to, from the one stored in the DB) take that number and add it to an integer column named something like elapsed time (you would have to add this to the DB)
if not then enter a row with 0 elapsed time ( depending how you put the first row in, maybe on login) this may never be an issue.
For the timestamps, you would do a select to get the current row. Take the datetime field and use either
$time = strtotime($row['last_activity']);
OR
$time = (new DateTime($row['last_activity']))->getTimestamp();
Then you simply do the same thing to the date you are going to replace that with and then subtract to get the difference in seconds.
$elapsed = time() - $time;
And then add that to the current rows value, and save it. This way you can keep track of a running total in seconds of the time they spend during that session.
Then when you need to count the total time its a simple matter of doing
SELECT SUM(elapsed_time) FROM {table} WHERE DATE(last_Ativity) = :date
If you were dealing with just two date time fields in the DB it would be easier to just get the difference of those, but sense you already have code to constantly update the last active field this would require less work in the long run IMO.
Option2
The other option is to add another Datetime field to put a start time or login time in. Then when you query you can convert them to their timestamps and subtract to get the difference.
This makes the SQL harder (when doing the SUM ), I can't really think off the top of my head how I would calculate the elapsed time on multiple rows and then sum them up. But it does simplify the PHP quite a bit. So which ever way works best for what you need. Think about if you need the utility to know when they logged in, or if you just want an easier way to calculate the time they spend.
Something like that.
Assuming that the only log happens based on user actions, and so, after 15 minutes (for example) the user is assumed logged out
And assuming you'd want daily total, the solution should be something like this:
SELECT
first.emp_id,
SUM(TIMESTAMPDIFF(MINUTE,first.last_acivity, DATE_ADD(IFNULL(last.last_acivity, first.last_acivity), INTERVAL 15 MINUTE))) as logged_minutes
FROM
(
SELECT
la1.*
FROM
last_acivity la1
LEFT JOIN last_acivity la2 ON
la1.emp_id = la2.emp_id AND la1.last_acivity < la2.last_acivity
AND la2.activity =< #date0
WHERE
la1.last_acivity >= #date0
AND la2.login_id IS NULL
) first
LEFT JOIN
(
SELECT
la1.*
FROM
last_acivity la1
LEFT JOIN last_acivity la2 ON
la1.emp_id = la2.emp_id AND la1.last_acivity > la2.last_acivity
AND la2.activity =< #date0
WHERE
la1.last_acivity >= #date0
AND la2.login_id IS NULL
) last
ON
first.emp_id = last.emp_id
GROUP BY
emp_id
In this query need to set the date seperately:
SET #date0 = DATE(NOW()) ;
To get the first record of the day, or the last, we need to LEFT join the table to itself, on the same emp_id BUT witn with an inequality, which will get for each emp record its ancestors or predecessors
When we add the NULL condition we bring the we get the edge case: first or last
What's left then is just calculating the minutes between the 2 tables
Since I assumed no log out record occurs, I treated the case when the first and last logins are the same, or no last login
Wanted to ask You how can I setup something on my php website, that would everyday automatically check and compare current date to all the database datetime entries and delete the rows of the dates that are in the past (for ex. if the current date is 2014-03-17, it would delete the rows that have datetime of 2014-03-16 ).
Because I basically have a TV-package website (not a real thing, just for a class), where you can order a package, you enter for how long and it adds that amount to current date, writes the order into database with the date written into a field named "expires". Would it make sense if I just wrote the checking function into the index, so when someone visits the site it would delete it? If so, how could I compare the two dates?
The DB example looks something like this: http://s29.postimg.org/7sbgj2hnr/dbtest.png
Although I highly recommend a scheduled task, you can do it in PHP by calling:
$sql = "DELETE FROM tableName WHERE `expires`<'".date('Y-m-d')."'";
Convert the date to a unix timestamp and compare it against the value of time() like you would any other integers.
It's hard to articulate the problem I'm having in the title, but here's the scenario: I'm working the backend of a 3-tiered exam taking website. I'm currently updating my function used for when students request an exam. The exam has start and end dates and times, as well as a time limit. What I want to do is specific to the case when the amount of time left in the exam period is less than the time limit for the exam, For example, the exam period ends at 5:00PM. The time is now 4:30PM. The exam time limit is an hour and a half. I want to replace the hour and a half time limit with 30 minutes. To do that, there are 3 dates I need, and I will explain how I get each:
Timestamp for my function page. When the controller calls my page, after I open the session, I set the default timezone to America/New York (my region). To get the timestamp, I use the code:
$date = date('Y-m-d H:i:s');
$currenttime = date('H:i:s', strtotime($date));
I use a function call to my database to acquire the time limit and the time the exam ends (I also use the dates for other comparisons to check exam availability). The exam end time is stored in resultant array $res[10] and the time limit is in $res[11].
Assuming the due date for the exam is equal to the date of the timestamp, and it is in the exam period (2 checks I perform before), I want to check if the difference between the current time and the end of the exam is less than the time limit. If the time until the exam ends is less than the time limit, I want to set that amount of time as the new time limit. My front end expects my result in the form HH:mm:ss (php's equivalent is H:i:s). So if there is 30 minutes until the exam ends and the time limit is an hour and a half, I want the new time limit to be 30 minutes (or 00:30:00). My code is currently not working as desired. I am meeting the criteria for the if statement, which is my desired result. When I am converting it to the form H:i:s is where the problem seems to be (I keep getting a result around 19:00:00). Every article I've read suggests to do it this way, but I may be missing something.
$compareTime = strtotime($res[10]) - strtotime($currenttime);
if(compareTime < strtotime($res[11]){
$timelimit = date('H:i:s', $compareTime);
}else{
$timelimit = $res[11];
}
If there is a better way of doing this, I'd be much obliged to know. I'm fairly new to php, and admittedly I realize this may be a strange problem, but that's the way the group decided to go.
Maybe it's because the databse and PHP server are using different timezones. Check it out by printing these variables to see their values.
First, an entry in the database:
I have an input form that writes start date, start and end times (in hour and minute) of working days plus lunch break in minutes (in the example dato=date, modetime=start hour, modeminut=start minute, fyrtime=end hour, fyrminut=end minute). I need to do several calculations:
First calculate the date, start hour and minute into the datetime field modetid.
The do a similar calculation with the end hours and minutes, but move the date up one day if end hours is less than start hour (lets call it fyrtid)
And finally calculate the difference between fyrtid and modetid minus the pause minutes.
Can it be done directly and automatically in the database (if yes, how) or do I need some PHP to do it (and again, if yes, how)?
I know its a tall order but I have not been able to find much information on date/time calculations that made much sense on my low level of knowledge. Any link to a comprehensive guide on date/time calculation in MySQL or PHP would also be greatly welcomed.
I suggest you to work by php function time() it's based on unix timestamp ( like UNIX_TIMESTAMP() in Mysql ) unix time is like this : 1307387678.
Use a calender in your form for start time also for your end time.
put a facility what clients could select time of day ( hour and minutes ) then covert those fileds by strtotime() to unix timestamp like following code ( set date format to mm/dd/yyyy ) :
$startdate = strtotime ( "$_POST['calender_start'] $_POST['hour_start']:$_POST['minutes_start']" );
$enddate = strtotime ( "$_POST['calender_end'] $_POST['hour_end']:$_POST['minutes_end']" );
Change your db table fields to : cpr,startDate,endDate,pause,basked,.....
it's so flexible.
while you want to fetch special recorde you could fetch rows by this sql :
SELECT ...... FROM [TABLE_NAME] WHERE [VALUE] BETWEEN startDate AND endDate
I hope it be usefull for you
I am trying to create a script for quiz. I have stored current timestamp in MySQL DB as quiz start time, and want to check after each quiz how much time is left.
I have the idea that I will add 30 mins to saved time stamp and subtract this value from current time. That will be the time left. But I don't know the exact way of doing this.
My time stamp is saved in DB in format 2010-08-24 20:08:59. Any one have the idea.
Please let me know if someone have done it, or know how to get it.
Adding 30 mins to time stamp and showing the user how much time is left.
I am using the now() function to store the timestamp in DB.
Thanks
I would personally store the output of PHP time() in the database.
If you a human readable format from this value, you could use date('Y-m-d H:i:s', $fromdatabase);.
You want to store an actual UNIX timestamp in the database, not a string in that format.
You may or may not be doing this already, it depends on the type of column you're using. For MySQL, you should be using TIMESTAMP, which allows you to retrieve the timestamp with
SELECT UNIX_TIMESTAMP(column_name) ...
To store the current time + 30 minutes, all you have to do is:
INSERT INTO table (column_name) VALUES(UNIX_TIMESTAMP() + 1800)
You can know if the time has expired by comparing time() against the value of the column.