Is there a way to grab the most recent time of day. If your data in the database is formatted like this 07:00AM and 08:00pm and 12:00pm. Sorta like max(). But for the time. In a Mysql query.
Thanks
Eric
It would be best to store it in another format rather than as text. Or at least store it in 24 hour format, then a simple sort would work. You can convert it to 12-hour format when you display the data to the user.
But assuming you can't change your database schema, try this:
SELECT *
FROM your_table
ORDER BY STR_TO_DATE(your_time, '%h:%i%p') DESC
LIMIT 1
Note that this won't be able to use an index to perform the sorting.
You should try STR_TO_DATE() instead if you're using a string. If your times are always formatted as hh:mmAMPM, you can use:
MAX(STR_TO_DATE(YourTimeField,'%h:%i%p'))
This converts your string to a time, without any need to split it up by substring or anything, so MySQL would then see 09:07AM as 09:07:00 and 02:35PM as 14:35:00, and then would easily be able to determine the MAX of it.
Assuming you are dealing with a DATETIME field in your MySQL, you can use this query to get the max time per day:
SELECT DATE(YourDateField), MAX(TIME(YourDateField)) FROM YourTable
GROUP BY DATE(YourDateField)
When you are dealing with a VARCHAR field, you can try a hack like this:
SELECT YourDateField, SUBSTRING(MAX(
CASE WHEN YourTimeField LIKE '%AM%' THEN '0' ELSE '1' END
+ REPLACE(YourTimeField, '12:', '00:')
), 2)
GROUP BY YourDateField
You can just sort.
select time_column from table order by time_column desc limit 1;
Related
I have DB of posts with:
post_id(int(7)) user_id(int(7)) post_txt(text) post_time(varchar(30)) likes_count(int(10))
(the post_time is look like this "5-4-2016 17:41")
I want to order it by "hot posts" e.g. "likes_count/post_time".
How can I do it?
This is how I do it now:
$que_post=mysql_query("select * from user_post order by post_id desc");
PS. I know that this is not how you save likes usually, but I do it for purpose
Edit-Example data:
97||25||Hello world||8-4-2016 14:19||19
The algorithm I want to use is time/likes. I know its bad algorithm, but I just want to understand the basics.
I would like to know if you know good algorithm for that
You should change type of post_time field to DATETIME (read manual).
All your lines have to be converted by some script to format YYYY-MM-DD HH:MM:SS. When you do it, everything will work.
Your problem appears cause of sorting by alphabet as text. For example: 01.01.2016 as text is less than 31.01.1999.
Assuming you can convert the post_time column to use a date type, you want to find the number of seconds between it and now, e.g.
Order By like_count / (unix_timestamp(now()) - unix_timestamp(post_time)) Desc;
If changing the column type isn't an option, you can convert it on-the-fly using the str_to_date function, but that will potentially be quite a slow operation.
I have a PHP scirpt that is always querying all the data from a database table and it's getting pretty slow. I really just need the data of a specific month and year.
Is there a simple way to get only those entries? For example, everything from February 2013?
The column that stores the dates in my table is of type datetime, if that applies to the solution.
You can add that condition in the WHERE clause of your select statement. I would recommend using BETWEEN operand for two dates:
SELECT myColumns
FROM myTable
WHERE dateColumn BETWEEN '2013-02-01' AND '2013-02-28';
If you mean to say you want everything beginning with February 2013, you can do so using the greater than or equal to operator:
SELECT myColumns
FROM myTable
WHERE dateColumn >= '2013-02-01';
EDIT
While the above are my preferred methods, I would like to add for completeness that MySQL also offers functions for grabbing specific parts of a date. If you wanted to create a paramaterized query where you could pass in the month and year as integers (instead of a start and end date) you could adjust your query like this:
SELECT myColumns
FROM myTable
WHERE MONTH(dateColumn) = 2 AND YEAR(dateColumn) = 2013;
Here is a whole bunch of helpful date and time functions.
You should index the datetime field for added efficiency and then use Between syntax in your sql. This will allow the mysql engine to remove all records that you are not interested in from the returned data set.
I have a case to query the table using WHERE clause in which I just want to use a 'piece of string' from the field to compare to my string as a condition for selecting.
In the picture, I just want to use month and year from date field to compare with $indicator = 03/2013.
Any idea how can performing the query, so the result would look like:
Any help will appreciated. Thank you in advanced.
Most likely, you aren't dealing with strings in the table, as it's most likely dates. If you are dealing with strings, it's
SELECT * FROM table WHERE DATE LIKE '%03/2013';
where % is a wildcard like * in the old dos days
For actual date fields, (which you would be better off using), it's a simple between
SELECT * FROM table WHERE DATE BETWEEN '01/03/2013' AND '31/03/2013'
Note that you need to follow proper date formatting for your engine, for something like MySQL you'd be better off using '2013-03-01' and '2013-03-31'
The hardest part will be coming up with the first and last day, but for that, I'd look at strtotime(), which allows you to put in things like 'Last day of the month' and such. You'd have to format it correctly, and play with the strings, but it's rather trivial with what strtotime() can do.
USE LIKE in your mysql query instead of =
Reference : (source)
Greetings hope to get some help from you here as i been searching high and low for this.
This query works but its not the results i wanted more correctly not the right date format i want it in.
SELECT DISTINCT colum FROM table WHERE colum IS NOT NULL
This query gives me the dates
01.04.13
02.04.13
03.04.13
30.03.13
31.03.13
I wanted it to show latest date.
This info is posted in colum that stores the info as text. It is posted in the following format
dd.mm.yy
I wanted it then to show me the results as in
03.04.13 since this is todays date. i know i can limit it to 1 but still it will show the wrong date.
Thank you again for all help so far
First, you should not be storing a date as a string, you should store a data as a DateTime datatype.
Since you are storing it as a string, you will have to convert it to a date to get the max() date value. The following uses the STR_TO_DATE() function to convert the string to a date to get the max value:
select max(str_to_date(yourdate, '%d.%m.%y')) MaxDate
from table1
See SQL Fiddle with Demo
Try
select distinct column from tab where column1 = date_format(curdate(),'%d.%m.%y') AND brukernavn is not null order by brukernavn;
1) You need to save DATES in date or datetime
2) try MAX() function in MySQL
or try to ORDER BY date DESC and LIMIT 1
3) by the way, did you try using DISTINCT with GROUP BY?
I have two field in a database table departureDateTime and arrivalDateTime and the values like
departureDateTime=03/18/2012 1:05 PM
arrivalDateTime=03/18/2012 3:15 PM
I have hundreds of records in the table.
I need to sort and display according to the duration from these two time. I know to calculate the duration from two dates
Duration=(strtotime($arrivalDateTime') - strtotime($departureDateTime))/3600
But how I write a mysql query to sort and display these 100 records from database
Does any one any idea?
Thanks
Change your departureDateTime to DATETIME instead of varchar or whatever you are currently using. Then you would use something like this:
SELECT other, stuff, TIMEDIFF(departureDateTime, arrivalDateTime) as theDifference FROM myTable ORDER BY theDifference ASC LIMIT 0, 100
If you kept your date and times in a date time column type then you wouldn't have this problem. Consider changing.
There are mysql functions to calculate dates and time too
http://dev.mysql.com/doc/refman/5.6/en/datetime.html
If not, you can do sorting in PHP using usort.