I can't seem to get reliable results from the query against a sqlite database using a datetime string as a comparison as so:
select *
from table_1
where mydate >= '1/1/2009' and mydate <= '5/5/2009'
how should I handle datetime comparisons to sqlite?
update:
field mydate is a DateTime datatype
To solve this problem, I store dates as YYYYMMDD. Thus,
where mydate >= '20090101' and mydate <= '20050505'
It just plain WORKS all the time. You may only need to write a parser to handle how users might enter their dates so you can convert them to YYYYMMDD.
SQLite doesn't have dedicated datetime types, but does have a few datetime functions. Follow the string representation formats (actually only formats 1-10) understood by those functions (storing the value as a string) and then you can use them, plus lexicographical comparison on the strings will match datetime comparison (as long as you don't try to compare dates to times or datetimes to times, which doesn't make a whole lot of sense anyway).
Depending on which language you use, you can even get automatic conversion. (Which doesn't apply to comparisons in SQL statements like the example, but will make your life easier.)
I had the same issue recently, and I solved it like this:
SELECT * FROM table WHERE
strftime('%s', date) BETWEEN strftime('%s', start_date) AND strftime('%s', end_date)
The following is working fine for me using SQLite:
SELECT *
FROM ingresosgastos
WHERE fecharegistro BETWEEN "2010-01-01" AND "2013-01-01"
Following worked for me.
SELECT *
FROM table_log
WHERE DATE(start_time) <= '2017-01-09' AND DATE(start_time) >= '2016-12-21'
Sqlite can not compare on dates. we need to convert into seconds and cast it as integer.
Example
SELECT * FROM Table
WHERE
CAST(strftime('%s', date_field) AS integer) <=CAST(strftime('%s', '2015-01-01') AS integer) ;
I have a situation where I want data from up to two days ago and up until the end of today.
I arrived at the following.
WHERE dateTimeRecorded between date('now', 'start of day','-2 days')
and date('now', 'start of day', '+1 day')
Ok, technically I also pull in midnight on tomorrow like the original poster, if there was any data, but my data is all historical.
The key thing to remember, the initial poster excluded all data after 2009-11-15 00:00:00. So, any data that was recorded at midnight on the 15th was included but any data after midnight on the 15th was not.
If their query was,
select *
from table_1
where mydate between Datetime('2009-11-13 00:00:00')
and Datetime('2009-11-15 23:59:59')
Use of the between clause for clarity.
It would have been slightly better. It still does not take into account leap seconds in which an hour can actually have more than 60 seconds, but good enough for discussions here :)
I had to store the time with the time-zone information in it, and was able to get queries working with the following format:
"SELECT * FROM events WHERE datetime(date_added) BETWEEN
datetime('2015-03-06 20:11:00 -04:00') AND datetime('2015-03-06 20:13:00 -04:00')"
The time is stored in the database as regular TEXT in the following format:
2015-03-06 20:12:15 -04:00
Right now i am developing using System.Data.SQlite NuGet package (version 1.0.109.2). Which using SQLite version 3.24.0.
And this works for me.
SELECT * FROM tables WHERE datetime
BETWEEN '2018-10-01 00:00:00' AND '2018-10-10 23:59:59';
I don't need to use the datetime() function. Perhaps they already updated the SQL query on that SQLite version.
Below are the methods to compare the dates but before that we need to identify the format of date stored in DB
I have dates stored in MM/DD/YYYY HH:MM format so it has to be compared in that format
Below query compares the convert the date into MM/DD/YYY format and get data from last five days till today. BETWEEN operator will help and you can simply specify start date AND end date.
select * from myTable where myColumn BETWEEN strftime('%m/%d/%Y %H:%M', datetime('now','localtime'), '-5 day') AND strftime('%m/%d/%Y %H:%M',datetime('now','localtime'));
Below query will use greater than operator (>).
select * from myTable where myColumn > strftime('%m/%d/%Y %H:%M', datetime('now','localtime'), '-5 day');
All the computation I have done is using current time, you can change the format and date as per your need.
Hope this will help you
Summved
You could also write up your own user functions to handle dates in the format you choose. SQLite has a fairly simple method for writing your own user functions. For example, I wrote a few to add time durations together.
My query I did as follows:
SELECT COUNT(carSold)
FROM cars_sales_tbl
WHERE date
BETWEEN '2015-04-01' AND '2015-04-30'
AND carType = "Hybrid"
I got the hint by #ifredy's answer. The all I did is, I wanted this query to be run in iOS, using Objective-C. And it works!
Hope someone who does iOS Development, will get use out of this answer too!
Here is a working example in C# in three ways:
string tableName = "TestTable";
var startDate = DateTime.Today.ToString("yyyy-MM-dd 00:00:00"); \\From today midnight
var endDate = date.AddDays(1).ToString("yyyy-MM-dd HH:mm:ss"); \\ Whole day
string way1 /*long way*/ = $"SELECT * FROM {tableName} WHERE strftime(\'%s\', DateTime)
BETWEEN strftime('%s', \'{startDate}\') AND strftime('%s', \'{endDate}\')";
string way2= $"SELECT * FROM {tableName} WHERE DateTime BETWEEN \'{startDate}\' AND \'{endDate}\'";
string way3= $"SELECT * FROM {tableName} WHERE DateTime >= \'{startDate}\' AND DateTime <=\'{endDate}\'";
select *
from table_1
where date(mydate) >= '1/1/2009' and date(mydate) <= '5/5/2009'
This work for me
Related
I'm trying to make a query that will look like
SELECT * from `table` WHERE args
I need to have my args the date from 'yesterday' and time 23:00 until date'Today' and time 22:59.
I'm very bad at writing SQL and I will need masters help for this one.
I know how to write basic SQL and I'm not sure how to write.
Date and time are 2 different rows.
Basic SQL stuff.
Expecting all data from date yesterday starting with time 23:00 until date = today and time = 22:59
Logically is simple, I'm just bad at writing SQL logic.
Date has to be always generated based on current date, time will be static.
SELECT * from `table` WHERE date= Yesterday And time= 23:00 TO date=today time=22:59
Edit:
Database is MariaDB from Xamp
Assuming this is MySQL (MariaDB) and there are in fact two columns called date and time this could be written as
SELECT * FROM `table` WHERE
(date = SUBDATE(CURDATE(), 1) AND time >= '23:00') OR (date = CURDATE() AND time < '23:00');
This is a bit unusual though. Usually you would have as single column of type datetime or timestamp instead of two columns, and they should not be called date or time because these are keywords.
You may try the below query:
SELECT * FROM `table` WHERE date BETWEEN CONCAT(date_sub(curdate(),interval 1 day),' 23:00') AND CONCAT(curdate(),' 22:59');
Please double check your database timezone.
I have an integer date column "date_created" storing values like...
20180527, 20191205, 20200208
And am wondering what the best way to parse as a date is so I could do something like this in a query...
select * from table where formatted(date_created) > formatted(date_created) - 90
(to return everything within the last 90 days)
I've found some similar examples that convert from date ints representing seconds or milliseconds, but none where the columns are essentially date strings stored as integers.
Appreciate any thoughts on the best way to achieve this
And am wondering what the best way to parse as a date is so I could do something like this in a query...
You can convert "date as a number" (eg. 20180527 for May 27, 2018) using the following:
cast to varchar
parse_datetime with appropriate format
cast to date (since parse_datetime returns a timestamp)
Example:
presto> SELECT CAST(parse_datetime(CAST(20180527 AS varchar), 'yyyyMMdd') AS date);
_col0
------------
2018-05-27
However, this is not necessarily the best way to query your data. By adapting your search conditions to the format of your data (and not vice versa), you can potentially benefit from predicate push down and partition pruning. See #GordonLinoff answer for information how to do this.
You can do the comparison in the world of integers or of dates. You might as well convert the current date minus 90 days to a number:
select t.*
from t
where date_created >= cast(date_format(current_date - interval '90 day',
'%Y%m%d'
) as int
);
the below query is index friendly for any database since it does not use function on indexed column
select * from table where date_created > timestamp (formatted(date) - 90)
In addition, suppose we have date in format 20211011_1234 and we want one month older date and want back the original format, we can use the following formatting to convert date to int and vice versa.
select cast(date_format(
CAST(parse_datetime(cast(
split_part('20211011_1234', '_', 1) as varchar), 'yyyyMMdd')
AS date) - interval '30' day ,'%Y%m%d') as int) as column_name
I am using Microsoft SQL Server and I have a table with a datetime column.
When I run a query SELECT END_DATE FROM CUSTOMER I get 2007-12-03 10:15:30.000
I would like to run a query that returns a unix timestamp like 1543357818 representing the date and time. Is this possible through SQL?
Just use datediff():
SELECT DATEDIFF(second, '1970-01-01', END_DATE)
FROM CUSTOMER
As an alternative, convert to float and do a subtract, then convert to seconds. Obviously you can change some of this to constants, but this illustrates what I'm doing:
select floor((convert(float,getdate())-convert(float,convert(datetime,'1970-01-01')))*24*60*60)
I have a Sql server table which contains below Date values(4th october)
Now Below query is not showing any result
select
*
from [dbo].[TB_AUDIT] TBA
where TBA.ActionDate >= '10/01/2018' and TBA.ActionDate <= '10/04/2018' which is not correct.
But If I write
select
*
from [dbo].[TB_AUDIT] TBA
where TBA.ActionDate >= '10/01/2018' and TBA.ActionDate <= '10/05/2018' it is returning me all results.
What I am doing wrong.
There are two problems with this query. The first, is that it's using a localized string. To me, it looks like it's asking for rows between January and April. The unambiguous date format is YYYYMMDD. YYYY-MM-DD by itself may not work in SQL server as it's still affected by the language. The ODBC date literal, {d'YYYY-MM-DD'} also works unambiguously.
Second, the date parameters have no time which defaults to 00:00. The stored dates though have a time element which means they are outside the search range, even if the date parameter was recognized.
The query should change to :
select
*
from [dbo].[TB_AUDIT] TBA
where
cast(TBA.ActionDate as date) between '20181001' and '20181004'
or
cast(TBA.ActionDate as date) between {d'2018-10-01'} and {d'2018-10-04'}
Normally, applying a function to a field prevents the server from using any indexes. SQL Server is smart enough though to convert this to a query that covers the entire date, essentially similar to
where
TBA.ActionDate >='2018:10:01T00:00' and TBA.ActionDate <'2018-10-05T00:00:00'
When you don't specify a time component for a DATETIME, SQL Server defaults it to midnight. So in your first query, you're asking for all results <='2018-10-04T00:00:00.000'. All of the data points in your table are greater than '2018-10-04T00:00:00.000', so nothing is returned.
You want
TBA.ActionDate >= '2018-10-01T00:00:00.000' and TBA.ActionDate < '2018-10-05T00:00:00.000'`
Use properly formatted dates!
select *
from [dbo].[TB_AUDIT] TBA
where TBA.ActionDate >= '2018-10-01' and TBA.ActionDate <= '2018-10-04'
YYYY-MM-DD isn't just a good idea. It is the ISO standard for date formats, recognized by most databases.
when you just filter by the date, it is with regard to the time as per the standard.
I have a HSQLDB table with some informations and where a timestamp is stored
I want to select informations from specific time periods like every information of october between 0am and 5pm.
I didn't found any function like mysql'ones DATE(myfield) OR TIME(myfield) which would be perfect for what i want.
SELECT * FROM myTable
WHERE DATE(myField) BETWEEN '2012-10-01' AND '2012-10-30'
AND TIME(myField) BETWEEN '00:00:00' AND '17:00:00'
The only things i found are to use the functions YEAR(), DAYOFMONTH(), DAYOFYEAR(), HOUR() ANd MINUTE() but I was wondering if there aren't any other simpler solutions.
There is no need for such specialised functions as HSQLDB supports the general CAST expression for this purpose
CAST(myField AS DATE)
CAST(myField AS TIME)
HSQLDB also supports automatic cast from DATE to TIMESTAMP. Therefore an optimised query that can use an index on the myField column should look like this:
SELECT * FROM myTable
WHERE myField BETWEEN DATE'2012-10-01' AND DATE'2012-10-30'
AND CAST(myField AS TIME) BETWEEN TIME'00:00:00' AND TIME'17:00:00'