I have a temp table.
It has last_update column in 2/10/2018 6:01:50 PM datetime format.
How can I write THE BEST QUERY to display all information that's updated on 02-Oct-2018 day?
You can use trunc function
select *
from tab
where trunc(last_update) = date'2018-10-02'
It is preferable to avoid TRUNC especially if you have an index on the column last_update.
A simple where condition should be better and may be better performant.
WHERE last_update >= date '2018-10-02' AND
last_update < date '2018-10-02' + 1
Use trunc function for getting the same day:
trunc(last_update) = trunc(to_date('02-Oct-2018', 'DD-MONTH-YYYY'))
The TRUNC (date) function returns date with the time portion of the day truncated to the unit specified by the format model fmt. The value returned is always of datatype DATE, even if you specify a different datetime datatype for date. If you omit fmt, then date is truncated to the nearest day.
You can also use format DD-MON-YYYY
Related
I have seperate date and time columns in my table. Date as mm/dd/yyyy, time as hh:mm but i can change the format. I want to list data between 2 date/time. How can I do that?
select * from testtable where date >= '01/10/2022' AND date <= '01/10/2023' AND time >= '13:45' AND time <= '15:50'
I wrote it but of course it doesn't work like what i expected.
The best fix and really the only one you want here would be to start storing your timestamps in a sortable ISO format yyyy-mm-dd hh:ii:ss. Then, use this query:
SELECT *
FROM testtable
WHERE date BETWEEN '2022-01-10 13:45:00' AND '2023-01-10 15:50:00';
The thing to realize here is that SQLite does not actually have a date column type. Rather, you always store your dates/timestamps as text, and therefore it is crucial to use an ISO sortable format as shown above.
If your target is sqlite, it lacks complex timestamp types. But you have another option here. You can store that as unix timestamp, it is an integer representing the number of seconds offset from the epoch which is 1970-01-01 00:00:00 UTC. The table format would then be:
CREATE TABLE testtable (
date INTEGER
);
You can the use the unixepoch function to translate a string representation to that unix timestamp format. To insert a new date, you would use:
INSERT INTO testtable (date) VALUES (unixepoch('2023-01-11T11:30:00+01:00'))
Finding a matching row is now as easy to compare integers together. You can convert the datetime representation to unix timestamp at the application level, most programming environments provide such time utility functions/library. Or can still use the unixepoch function from sqlite for your where clause.
SELECT * FROM testtable
WHERE date >= unixepoch('2022-10-01T13:45:00Z')
AND date <= unixepoch('2023-10-01T15:50:00Z')
The final Z indicates an UTC time zone but you can adjust that with another +HH:00 extenstion instead which reflect the offset from utc of your datetime representation.
sql table
here in the table above named carpooling contains a column name start_on which has date time as timestamp i have to write a query to select all the rows having date as 25-11-20 using to_char and to_date.
You write a timestamp literal like this:
timestamp '2020-11-25 00:00:00'
so the full filtering condition will be
where start_on >= timestamp '2020-11-25 00:00:00'
and start_on < timestamp '2020-11-26 00:00:00'
Note that dates and timestamps are different in Oracle, and dates include times down to the second (this is for historical reasons - originally there was only the date type, and timestamp was added much later).
Use the TRUNC function, along with date and interval literals:
SELECT *
FROM CARPOOLING
WHERE START_ON BETWEEN DATE '2020-11-25'
AND (DATE '2020-11-26' - INTERVAL '0.000001' SECOND)
You can simply use to_date, but it's recommended to remove the time when comparing the dates. Otherwise, rows having the same date, but a different time will not be selected. Removing the time can be done using TRUNC.
So you can do something like this:
SELECT * FROM carpooling
WHERE TRUNC(start_on) = TO_DATE('2020-11-25','yyyy.mm.dd');
If you don't want to check the 25th of November 2020, but another data, change the date to match your goal.
I have Oracle SQL query where it has been used TRUNC(04-Aug-2017 15:35:32)
What will be parameter in Hive to replace TRUNC?
Assuming you have a date/time, you can use the to_date() function:
select to_date(col)
If you have a timestamp, say ts, you can use trunc():
trunc(ts, 'day')
This returns a timestamp, with the time portion stripped off - which is similar to what trunc() does in Oracle when given one argument only.
On the other hand, you can also convert the timestamp to a date:
to_date(ts)
This returns a date rather than a timestamp: that's a different datatype, that has no time component (Oracle does not have such a datatype: both date and timestamp store the date and time).
As per Oracle docs, The TRUNC (date) function returns date with the time portion of the day truncated to the unit specified by the format model fmt. The value returned is always of datatype DATE, even if you specify a different datetime datatype for date. If you omit fmt, then date is truncated to the nearest day.
Similar is the function of to_date function in Hive.
It returns the date part of a timestamp string (pre-Hive 2.1.0): to_date("1970-01-01 00:00:00") = "1970-01-01".
If what you want is the timestamp(midnight timestamp : 00:00:00) along with the truncated date, you need to use some conversions as shown below:
cast(from_unixtime(unix_timestamp(to_date(<YOU_DATE_COL>), 'yyyy-MM-dd')) as timestamp)
I have a date/time stamp field, where I need to pull records just by date.
Example: All data were records are >= '01/01/2016'.
The data in the field is store in the following format '9/5/2012 7:34:59 AM'
I have tried the following but either I get an error or bad results:
where to_char(start_time) > '01/01/2016' (still gives 2012 records)
where trunc(start_time) > '01/01/2016' (Error: Not a valid month)
In mysql you should use
this is in string canonical format
select * from my_table
where start_time > '2016/01/01'
or
or converting by str_to_date using proper format
select * from my_table
where start_time > str_to_date('01/01/2016', '%d/%m/%Y')
Use to_date to convert the string to date and then do the comparison.
Try this:
where start_time >= to_date('01/01/2016', 'dd/mm/yyyy');
In Oracle (and perhaps other database products) you can use the ANSI date literal, as shown below. You could also use to_date(), but the benefit of the ANSI date literal is that it doesn't require a function call. (Function calls are overhead which consumes time and resources, although calling to_date() just once is not a concern.)
... where start_time >= date '2016-01-01'
Note that in the ANSI standard date literal, the date must be in the exact format YYYY-MM-DD (with dashes and not with slashes or any other separators), since the ANSI date literal does not take a format model.
For instance, I have a datetime like this '2016-04-02 00:00:00' and another like this '2016-04-02 15:10:00'. I don't care about the time-part, I want them to match just by the date-part.
I have tried with date(), to_date, datepart, nothing works.
Do it like this:
where yourField >= the start of your date range
and yourField < the day after the end of your date range
Edit starts here:
While you could use trunc, as suggested by others, bear in mind that filtering on function results tends to be slow.
Truncating the date to day should do the trick. Documentation here:
https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions201.htm
For example
SELECT TRUNC(SYSDATE, 'DAY') FROM DUAL;
As others have said - there is no separate "date" data type in Oracle. A pure "date" is stored as a date with the time portion set to 00:00:00 (midnight at the beginning of the day), and TRUNC(date) will take any date and truncate the time to 00:00:00, so if you need to compare two dates you can write
where trunc(date_1) = trunc(date_2)
If your tables are very large and you need to do these comparisons often, this is not ideal, because wrapping column values within function calls (like date_1 within a TRUNC) prevents the use of an index you may have on the date_1 column. If you need to compare dates in two columns you may not have much of a choice, but if you compare to a fixed date (or something like SYSDATE) you may be better off with something like
where date_1 >= trunc(sysdate) and date_1 < trunc(sysdate) + 1
Here you are not using trunc on the column value, so if there's an index on the column, Oracle is free to use it - and trunc(sysdate) is computed only once, not for every single row. "+1" by the way means "add one day".
TO_DATE converts a string to a date; if you apply TO_DATE to a value that is already a legitimate date, you will get unexpected results because Oracle will first convert your true date to a string and then back to date again, and since these conversions require a date FORMAT for strings, and the formats Oracle assumes for conversion from date to string and from string to date may not match, .... you get the idea. As far as I know, DATE() (a FUNCTION) and DATEPART do not exist in Oracle; when you use a new language, keep Google close by and use it often.
If you input a date with no time component, for example TO_DATE('04-apr-2016, 'dd-mon-yyyy'), then the implicit time is 00:00:00 so you don't need to apply TRUNC() to it.
Good luck!