In my DB there is a date-time (slot_start) field. Unfortunately the entries are expressed in two different time zones.
For example: 2021-02-08T08:00:00+01:00 and 2021-02-08T07:00:00+00:00
Now I'm trying to list all entries in Central European Time (CET).
I have tried the following:
SELECT customer_nicename,
service_name,
CONVERT_TZ(slot_start,'+00:00','+00:00') AS Slot_Start,
status
FROM reservations
WHERE status LIKE 'confirmed'
But one of the two time zones are expressed shifted by an hour.
I dont get any further - can somebody help me out?
Thanks a lot!
Related
Developers, I am working on a report that I have to display the companies ranking based on some conditions for the date range which comes from front. Ex: last week, I have done that, but now I want to show how many weeks that a particular company be in same rank. If I am checking the past week I have to check the ranking for each week from the year start. If last week first position company and other weeks first position company is same I have make the count as increasing accordingly. When I querying the data for each week using the for loop it is taking around 42s to process and display the data. Also I tried to fetch whole data from first week of the year to current week then I filtered the array but this also takes long time. Can anyone give any other ideas to overcome this? Thanks in advance.
As far as I understand your problem - then storage of aggregated data should help you.
Create a table in the database, let's say "archive_rating", with 3 fields: week_number (let from January 1, 2000), company_id, company_position in your rating. Don't forget the index for the week_number field.
At 00:00:00 every Monday, run a background task that will save the positions for each company to an archive table.
This will allow you not to calculate a rating for each week from the beginning of the year. You will already have it.
I am stuck with a problem. In an app's db, I am having a schedule table which will store user provided schedules. E.g
Daily
Every Week
Twice a Week
Every 3rd (or any user chosen) day of week
Every Month
Twice a month
Every x day of month
Every x month of year
And so on. These schedules will then provide reference point to schedule different tasks or identify their repeat-ance.
I am not able to think of a proper database structure for it. The best I can get is to have a table with following columns:
Day
Week
Month
Year
type
Then store the specified schedule in the related column and provide the type.
e.g Every week can go like 1 in week column and 1 (designated value for repeating whole) or something like that.
The problem with this approach is that this table is gonna be used very frequently and the data retrieved will not be straightforward. It will need calculation to know the schedule type and hence will require complex db queries to get each type of schedule.
I am implementing it in Laravel app if that can provide any other methodology. It's a SAAS app with huge amount of data related to the schedule table.
Any help will be very much appreciated. Thanks
I suggest you are approaching the problem backwards.
Devise several rules. Code the rules in your app, not in SQL. When inserting an event, pre-fill a calendar through the next 12 months with all occurrences of the event. Every month, go through all events and extend the "pre-fill" through another month (13 months hence).
Now the SELECTs are simple and fast.
SELECT ... WHERE date = '...'
has all the events for that day (assuming it is within 12 months).
The complexity is on inserting. But presumably you insert less often than you select.
The table with the event definitions would be only as complex as needed for your app to figure out what to do. Perhaps
start_date DATE,
frequency ENUM('day', 'week', 'month', ...)
multiplier TINYINT, -- this lets you say "every second week"
offset TINYINT, -- to get "15th of every month"
Twice a week would be two entries.
Better yet, there are several packages (in Perl, shell, etc) that provide a very rich language for expressing event-date-patterns. Furthermore, you may be able to simply 'call' it to do all the work for you!
I'm trying to help a taxi company. The problem is that they have a credit card machine that takes payments, and has its own database entries, and there is a completely separate database that has a list of entries such as pick up time, and drop off time.
I need to match the database of trip entries to the credit card purchases, and the only way to do this is by matching which vehicle is running the transaction, and looking for a time CLOSE TO the DROP OFF time and see if it's a match. It's not ideal.
So, I am trying to compare two times in yy-mm-dd hh:mm:ss format. They need to be plus or minus 5 minutes of each other. How do I do this in MYSQL?
I thought SubTime and Addtime would work, and it seemed to, but then I got wierd results.
SELECT * FROM completedtrans WHERE DrivID = 128 AND TransTime BETWEEN SUBTIME('2013-06-20 16:53:06', '0 00:05:00') AND ADDTIME('2013-06-20 16:53:06', '0 00:05:00')
Here's an example of one of my searches. Can anyone tell me what's wrong with it? It's supposed to search 5 minutes before and after that particular given time. I can't simply write the time, because the query is automatically generated through php code.
I'm working on an app that is partly an employee time clock. It's not too complex but I want to make sure I head in the right direction the first time. I currently have this table structure:
id - int
employee_id - int (fk)
timestamp - mysql timestamp
event_code - int (1 for clock in, 0 for clock out)
I've got everything working where if their last event was a "clock in" they only see the "clock out" button and visa-versa.
My problem is that we will need to run a report that shows how many hours an employee has worked in a month and also total hours during the current fiscal year (Since June 1 of the current year).
Seems like I could store clock in and outs in the same record and maybe even calculate minutes worked between the two events and store that in a column called "worked". Then I would just need to get the sum of all that column for that employee to know how much time total.
Should I keep the structure I have, move to all on one row per pair of clock in and out events, or is there a better way that I'm totally missing?
I know human error is also a big issue for time clocks since people often forget to clock in or out and I'm not sure which structure can handle that easier.
Is MySQL Timestamp a good option or should I use UNIX Timestamp?
Thanks for any advise/direction.
Rich
I would go with two tables:
One table should be simple log of what events occurred, like your existing design.
The second table contains the calculated working hours. There are columns for the logged in and logged out times and perhaps also a third column with the time difference between them precalculated.
The point is that the calculation of how many hours an employee has worked is complicated, as you mention. Employees may complain that they worked longer hours than your program reports. In this case you want to have access to the original log of all events with no information loss so that you can see and debug exactly what happened. But this raw format is slow and difficult to work with in SQL so for reporting purposes you also want the second table so that you can quickly generate reports with weekly, monthly or yearly sums.
Is MySQL Timestamp a good option or should I use UNIX Timestamp?
Timestamp is good because there are lots of MySQL functions that work well with timestamp. You might also want to consider using datetime which is very similar to timestamp.
Related
Should I use field 'datetime' or 'timestamp'?
I am new to database development and am currently working in MySQL.
I have a column that contains all the time zones for USA. I want to be able to get the current time (only time, no date) as of right now for each time zone in each row.
The TimeZone data looks like: +05:00, -03:00 etc etc etc
This is how I have attempted it. I have 2 tables, one country, one city. TimeZone is found within "city" table. I have tried to use the function sys date() but it returns the complete date and the current time on my system, not based on the time zone. Can anyone help me out? Thanks a lot
select TimeZone, Country, sysdate() as "Current Time"
from city, country
where Country='USA' and city.CountryId= country.CountryId;
You should be able to use the convert_tz function:
SELECT CONVERT_TZ(NOW(),'-07:00', city.TimeZone) AS Time, city.Name
FROM city, country
WHERE country.Name='USA' and city.CountryId= country.CountryId;
Assuming your server is in -07:00 timezone.