I am guessing this is relatively simple to do, but I am unsure of the syntax. I have date and time columns that I want to combine to a timestamp column. how would I query this using a select?
Or you could use the built-in TIMESTAMP(date,time) function.
So then you would do something like this say from an Orders table...
SELECT OrderNumber, TIMESTAMP(date,time) as OrderTS, SalesPersonID
FROM Orders
Mysql does not seem to have a constructor for datetime such as datetime('2017-10-26', '09:28:00'). So you will have to treat the component part as string and use string concatenation function (Note mysql does not have the || operator for string concatenation). If you want the datetime type, you will have to cast it.
concat(datefield,' ',timefield) as date
select cast(concat('2017-10-26', ' ', '09:28:00') as datetime) as dt;
If it possible to use built-in function, just use it.
Any way here is an example to find records between given timestamps.
SELECT `id` FROM `ar_time` WHERE TIMESTAMP(`cdate`,`ctime`) BETWEEN fromTimeStamp AND nowTimeStamp;
For 24hr time
TIMESTAMP(Date, STR_TO_DATE(Time, '%h:%i %p'))
SELECT * FROM tablename WHERE TIMESTAMP(datecol, timecol) > '2015-01-01 12:00:00';
O.P. did say SELECT but in case anyone wants to add a timestamp column:
ALTER TABLE `t` ADD COLUMN `stamp` TIMESTAMP;
UPDATE `t` SET `stamp` = STR_TO_DATE(CONCAT(`Date`, ' ', `Time`), '%m/%d/%Y %H:%i:%s');
Adjust format strings to taste.
concat('2021-12-31', ' ', '07:00:00')
it worked in an INSERT procedure.
Related
in a database table I have made a date attribute but I have set it's type to varchar and not Date.
My question is, will I still be able to compare such dates in a SQL Query?
Dates in my DB are stored in this format:
dd/mm/yyyy hh:mm:ss
I have to do a SQL Query in PHP that looks something like this:
SELECT *
FROM DBtable
WHERE DBname='$name' AND date>='01/01/2015' AND date<='01/09/2015';
I would appreciate an example how to do this.
Thank you for your help.
You'll need to convert/cast to compare:
SELECT *
FROM DBtable
WHERE DBname='$name'
AND CAST(date AS DATETIME) >='2015-01-01'
AND CAST(date AS DATETIME)<='2015-01-09'
;
Much better to store values as the appropriate data types to avoid this inefficiency. You could also use DATE instead of DATETIME if you want to compare without the time component. Syntax and available datatypes vary by database, so the above may need adjustment.
Update: Since you're using MySQL, you can use the following:
SELECT *
FROM DBtable
WHERE DBname='$name'
AND STR_TO_DATE(`date`, '%d/%c/%Y') >= '2015-01-01'
AND STR_TO_DATE(`date`, '%d/%c/%Y') <= '2015-01-09'
;
Yes you can cast a Varchar to a Date. Here is an example:
SELECT
CAST(date_column AS DATETIME)
FROM
TABLE_NAME
In your case it might look like:
SELECT *
FROM DBtable
WHERE DBname='$name'
AND CAST(date AS DATETIME) >='01/01/2015'
AND CAST(date AS DATETIME) <='01/09/2015';
You can cast or convert a varchar to a date or datetime before you do any comparisons.
But you'd have to do it every single time you compare the date to something. That's because the following comparisons are all true if you compare them as varchar:
'2/1/2015' > '1/5/2016'
'25/1/2015' > '15/2/2015'
'11/1/2015' < '3/1/2015'
You'll also need to convert if you want to pull out some time-based aspect of the dates, such as any records where the hour was before 8:00 AM. There is no easy way to do that if your date is a varchar.
And that assumes that the value in your database can always be parsed into a date! If an empty string or some other kind of data gets in there, CONVERT(datetime, MyColumn) will fail.
So I would strongly recommend that you change your column to be a date or datetime. It will make your life much easier.
I am trying folowing on my_table where modifiedtime is of type datetime
select DATE_FORMAT(modifiedtime,'%d-%m-%Y') from my_table
where DATE_FORMAT(modifiedtime,'%d-%m-%Y') between '05-11-2013' and '28-11-2013';
The query gives me some other record too which are not falls between above dates, for example there is a record in result set dated '04-01-2014'
select DATE_FORMAT(modifiedtime,'%d-%m-%Y') from my_table
where DATE_FORMAT(modifiedtime,'%d-%m-%Y')='05-11-2013'
this query works fine and gives all the records for the given date
why the first behaves like that?
How can i correct it?
what is the efficient way to implement it?
such that i can get all the records only between given two dates.
SELECT
DATE_FORMAT(modifiedtime, '%d-%m-%Y')
FROM
my_table
WHERE
modifiedtime BETWEEN STR_TO_DATE('05-11-2013', '%d-%m-%Y') AND STR_TO_DATE('28-11-2013', '%d-%m-%Y');
DATE_FORMAT() returns TEXT type column and dates can't be applied.
Use without DATE_FORMAT in the WHERE
select DATE_FORMAT(modifiedtime,'%d-%m-%Y') from my_table
where modifiedtime between '05-11-2013' and '28-11-2013';
you DATE_FORMAT function converts the column modifiedtime to String.
and hence in your first query you do a string comparison rather then a date comparison.
Also your date literal is not incorrect. It must be of form YYYY-MM-DD
select DATE_FORMAT(modifiedtime,'%d-%m-%Y') from my_table
where cast(modifiedtime as date) between '2013-11-05' and '2013-11-28';
i have created a date table directly through phpmyadmin and i want to split the date(yyyy:mm:dd) into individual day, month and year and insert into separate field. Can anybody help me in the query used directly in phpmyadmin to perform above work?
Try:
UPDATE `table` SET `year` = YEAR(`date`), `month` = DATE_FORMAT(`date`, '%m'), `day` = DATE_FORMAT(`date`, '%d')
I've used DATE_FORMAT() rather than MONTH() and DAY() as the latter two remove leading zeros.
In MySQL, I need to write a query (if possible) that finds all rows of a table where the date_created is the same as last_updated. The rub is that I need to ignore the time. Basically, I'm looking for user rows that were created and activated the same day (we don't store an activation date). So presumably the dates would be the same but the times may be different.
You could use the DATE() function, which returns only the date portion of a datetime value. This allows you to compare just the date portion of the values:
SELECT * FROM table_name
WHERE DATE(date_created) = DATE(last_updated)
The timezone may be relevant here. So you may want to cast the datetime values to the user's timezone prior to using the DATE() function, using CONVERT_TZ().
Try this:
SELECT *
FROM table_name
WHERE DATE_FORMAT(date_created, '%Y-%m-%d') = DATE_FORMAT(last_updated, '%Y-%m-%d')
not pretty but works:
SELECT *
FROM table_name
WHERE day(date_created) = day(last_updated) and
month(date_created) = month(last_updated) and
year(date_created) = year(last_updated)
I'm trying to make some vchar values searchable based on a date.
The strings I have to work with look like this:
1/7/2006 12:45:24 AM
1/7/2006 1:18:36 AM
1/7/2006 1:21:43 AM
1/7/2006 1:32:09 AM
3/30/2006 12:32:10 PM
3/30/2006 1:19:30 PM
3/30/2006 1:20:44 PM
So first off let's get rid of the AM.. PHPMyAdmin the sql query is:
SELECT trim('AM' FROM `orderdate`) FROM tblorders
This works to get rid of the AM now let's set the values as a variable and try to wrap a string to str_to_date() around the results:
SELECT trim('AM' FROM `orderdate`) AS `value`, STR_TO_DATE(`value`,'%d,%m,%Y') FROM tblorders
This yields value as an unknown column. How else do you string two function values together so as to then use them to be filtered such as WHERE value > 2/1/2006 ?
You can compose functions like this:
select str_to_date(trim('AM' from orderdate), '%m/%d/%Y')
Note that I also corrected your date format to match your data. You don't actually need to trim those values to use str_to_date on them, just this will work fine:
select str_to_date(orderdate, '%m/%d/%Y')
If you want to use that in your WHERE clause then put the function calls in there:
select trim('AM' from orderdate), str_to_date(orderdate, '%m/%d/%Y')
from your_table
where str_to_date(orderdate, '%m/%d/%Y') > '2006-01-02'
and let the optimizer recognize the repetition or use a derived table:
select value, the_date
from (
select trim('AM' from orderdate) as value, str_to_date(orderdate, '%m/%d/%Y') as the_date
from your_table
) dt
where the_date > '2006-01-02'
Note the use of ISO 8601 dates in the query, that format is unambiguous and any database worth using will understand it regardless of your locale settings.
I'd also recommend that you fix your schema to use real timestamps instead of those strings.