I have a dynamically changing mysql table(issuelist) with columns issueno.,issuetime and status. I display only issues with certain status(bad) in a html page.
"select issueno.,status from issuelist where status='bad' group by issueno.;"
Now I want to make the webpage static from Sunday to next Sunday, i.e., if the status of an issue changes from bad to good on tuesday, even then I want the page to display that particular issue with status = bad till next Sunday.
How can I achieve this?
You need to store the data somewhere in your database (for example you could add a column fixdate that would be NULL for issues with status that was good from the beggining or the date of the fix for the issues that changed status. That way, you could specify a static date to compare with the fixdate then show 'bad' or 'good' depending on the case.
Also you don't need to GROUP BY in a single table query with no operation
Related
I need some help about database management. I am trying to retrieve data from my database (filtering them by the created_at field).
There will be no problem when I am retrieving data from my database created in today's date.
For example today is 4/17. When I run the insert function today, the value for created_at will be 4/17 as well. So when I go to my web page and display data for 4/17, the data will be right.
But let's say I forgot to fetch data for 4/15, and I need to fetch those data today. When I insert these data in my database now, the created_at will be 4/17, but the adjacent data is actually for 4/15.
Now, when I go to my web page and display data for 4/15, I will get nothing.
As a workaround, I added a date field in my table, and this will contain a specified date, unlike the created_field that takes the server's date. I now use the date field to filter the data in my web page.
However, I think this is somewhat redundant or inefficient approach. Does anyone have any suggestions?
Here is a screenshot of my current table structure:
The accepted answer solves the XY problem. It's probably not the way to solve the actual problem.
There are lots of reasons for putting the current datetime into a database (rather than a datetime which is intrinsic in the data such as an appointment, or a date of birth). While this shouldn't be used for auditing purpose is it is handy for debugging and for dealing with optimistic locking.
But here, you seem to be looking for a transaction control mechanism - a way of identifying what records have been subjected to some action. If it is important to maintain a record of the sequence in which the records were processed, then a date, or even a date time, or even a millisecond timestamp may not be adequate. What happens iwhen you need to apply this operation more than once per day? What if it fails half way through and you need to resume the operation? This mechanism also precludes the notion that there may be more than 2 stati for a record.
Assuming the thing which is being done with the record is part of an ACID transaction, then there are 2 states to consider - before and after. Your data domain should explicitly describe those two states (using a null/non-null date value is merely implicit). If the transaction is not atomic then there will likely be more states to consider.
In the case of MySQL I would implement this as an enum datatype (with a non-null constraint). But more generally I seek to avoid a situation where data is being updated like this by using synchronous operations wrapped in transactions.
Since you are using Laravel, you can simply override the created_at value when creating your model. So for example, you can do the following:
$myModel->created_at = Carbon::parse('2019-04-15');
$myModel->save();
This would set the created_at value to April 15th, not today. Hence you don't need a second date column in your table.
UPDATE
Nonetheless, if you need the time part to still reflect the current time, you can do the following:
$myModel->created_at = Carbon::now()->setYear(2019)->setMonth(4)->setDay(15);
$myModel->save();
The user is able to enter the amount of rain collected each day, by entering the amount of rain collected, and date. They should be able to enter rain collected in the past as well (by giving another date if needed).
So, how can i check (by using the created_at row) if the user has already entered some data for the current date? And if they have, update the value given for the specific date. I already know how to update etc, I just need a way to validate the date given.
I was trying to figure something out by using Carbon, But my head is about to explode, I can't seem to wrap my mind around this issue.
'created_at','>=',Carbon::today())
I know that wont work. The created_at looks like this:
2014-07-16 20:42:38
So I would need a way to check the current date, and skip the time/clock? How would my approach be on this?
Create your condition in query like below, to match only date in yyyy-mm-dd, to check the current date.
->whereDate('created_at','=',Carbon::today()->format("Y-m-d") )
Carbon::now()->toDateTimeString();
See how you can work with dates
I am making an auction website, where users can add products, and set the end date.
My table enddate is like: 2015-2-25 14:01:23
and to determine if the item is ended I have a row called ended which can be 0 or 1. While I am writing this, I am thinking maybe I should check if time(system) is after or before enddate row to determine if the item is ended...
Anyway How would I go about changing the row ended to 1 on the exact time and date (even if someone's not viewing the page to run an ajax script) Would I have to do chron, or would it be better if I done what I mentioned above regarding checking the times?
Which one would you recommend? If using row ended how would I accomplish updating this on the enddate time.
Well, that's not the way to use a database. Your own suggestion is the way to go: Check if the current time is after or before enddate row to determine if the item has ended...
I've been tinkering with PHP lately (self-taught, no formal training), trying to understand how to grab data from a database and display the data somewhere. So far I have learned quite a bit, but now I am stumped.
I have a list of about 200 users in my local database in a table called site_members. The table has three fields: id, name, birth_date. Via PHP, I want to display all the users on a webpage, and have something like "Birthday soon!" be mentioned right after their name. Something like this:
John Smith (Birthday soon!)
I haven't written the code to do this, because I usually write pseudocode first before actually diving into the coding part. Here's the pseudocode:
Get the current date and time and convert it to Unix timestamp
Start foreach loop and go through list of users
Query the database table, get the birthdate of a user by their id, and store it in a variable named bdate.
Convert bdate to Unix timestamp
Subtract the current date from bdate, convert it into days remaining, and store it in a variable called remaining_days.
If the user's bdate is within 15 days (remaining_days is less than 15)
Display their name, followed by (Birthday soon!)
otherwise
Just display their name only
End if
End foreach loop
Here's my problem: With the above pseudocode once translated into actual code, there would be a database query made every time in that foreach loop. Some of the tutorials I consulted mentioned I should avoid that for efficiency reasons, and it makes sense. I ran Google searches to find something similar, but that didn't do much. I do not want anyone to write any actual code for me. I just want a better solution to the querying.
Thanks in advance!
I think your concept for the pseudo code is right, and you're understanding of doing multiple database queries is also right, you just tangled the two into giving you a wrong idea.
If you construct your select statement properly (that's basically what you'd be using to access the database), you actually pull the information for everyone out of the database and store it once in an array (or some other form of object). You can then start your foreach loop using the array as your value and perform the rest of your checks that way.
$date = date("m.d.y");
$people = ** insert your commands to grab the info from the DB **
foreach($people as $person) {
// do your comparison checks and echo's etc in here
}
Does this make sense?
There can be two solutions to your problem:-
1:
Instead of making query for every user, first get the data for all the users.
Traverse the data using foreach loop php
Do the processing and display the results.
2:
Store the user date_of_birth in proper mysql date datatype
Change your mysql query to use date function to get all the users who match your date difference criteria and just display those users.
It seems you failed to read up properly on the relationship between SQL and PHP. If you actually posted code, then you could have been easily unstumped because there are many ways to do the simple task from legacy tutorials to current PDO or even MVC within in 5mins or less.
I'm not going to write the code but you need to change HOW you think in your "pseudo code".
The problem with your pseudo code is because you believe that the DB is not smart and you are doing it as if it was only for storage.
The correct pattern for PHP is the following:
1) use the Date function to retrieve current day + 15. Get month and
day only.
2) you make a SQL query that retrieve all users who's
birth_date field's month and day are GREATER THAN (or equal) to
TODAY and who are less than or equal to today + 15 (day and month
only)
3) execute the query.
4) with the returned data set (if any)
you can choose two path depending situation and design
a) you can loop it with a simple FETCH which fetch each row retrieve
and display name and extra message.
or
b) iterates through the result set and store the display message
into a variable and then finally display it once the iteration is
done.
(option b is prefered because its more flexible since you can use this technique to out into a file instead of an echo)
THIS pseudo-code ensures that you are only retrieve the correct data set with the aid of the SQL system (or storage system).
In terms of overall process, aashnisshah is absolutely correct. First, you should retrieve all the records you need from your database then loop through each row to do your data comparisons and finally close the loop.
As for finding out if their birthday is close and if you want MySQL to do the hard work, you can build your query like that in PHP:
$query = "SELECT *, DATEDIFF(DATE_FORMAT(dob, '" . date('Y') . "-%m-%d'), CURDATE()) AS days_to_dob FROM Members";
The idea is to fetch an extra column called 'days_to_dob' containing the amount of days until that person's date of birth. Note that it will be negative if that date has passed for this year. With that extra column you can easily evaluate whether their dob is within 15 days.
If you don't want any php code, then here is my pseudocode:
Get date and time -> UTC stamp and store in $time_current
Get all from site_members and store in $data
for each entry in $data, store in $record
get birth_date from $record and convert to utc stamp and store in $birthday
print name from $record
if $birthday is close to $time_current then print "Birthday soon" end if
print new line
end for
That performs only one request to your database.
I'm new to MySQL and PHP but was wondering if someone could help me with a little project I'm doing for my boss.
I have a SQL database (MyDB) and a table in there (mytable) with two columns - the first column (index) is an auto-incrementing integer from 1-10, the second column (date) has different dates and timestamps in the format of Year-month-day time 2013-04-12 1326
I'm trying to create a simple PHP page that first gets the current date (easy enough) then looks at the table and shows the number of rows that fall within yesterday's date. For example, if I have 3 rows with 2013-04-11 XXXX and 2 rows with 2013-04-12 XXXX (and today is the 12th April 2013) the page will display 3. (The time is not important but we can't remove it from the table as it's auto created by one of the other staff's programs and he refuses to change it).
So far I've got my php page, done a connection to the DB and defined two variables:
$startdate = date('Y'."-".'n'."-".'d'." "."0000");
$enddate = date('Y'."-".'n'."-".'d'." "."2359");
As the timestamp doesn't matter I've gone for the min/max possible on the variables. I realise this will only give the current date, trying to work out how to get it to display the previous day as the date in the variable.
Now I'm trying to create a sql query that will count the number of rows where the date field falls within the startdate and enddate variables (-1 day) but not too sure where to start or how this would look. I then need to output this as a variable in PHP so I can echo it later in the page.
Anyone able to point me in the right direction? Hope any of this makes sense.
You could write a query with no params to do this (if its always just yesterday).
SELECT * FROM <table>
WHERE DATE_FORMAT(<date column>,'%j-%Y') = DATE_FORMAT(DATE_SUB(now(),INTERVAL 1 DAY), '%j-%Y');
Date functions in the where clause might not be super awesome performance wise