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I've been trying to query rows with a date field up to a threshold. For reasons beyond my control, all fields are varchar. I'm trying to filter out null values which case an error when cast. My latest attempt:
SELECT *
FROM a_table AS t
WHERE (
CASE
when t.dateField is not null then cast(t.datefield as date)
else cast('2000-01-01' as date)
END
) <= cast('2017-08-19' as date) ;
The above code still hits an error trying to cast "" to a date.
I thought this would be a common problem but I can't seem to find an idiom to achieve this, which makes me think I'm barking up the wrong tree. Can anyone point me to the correct one?
EDIT: Where entries are not null, they have been entered as DD/MM/YYYY.
You can use coalesce():
SELECT *
FROM a_table AS t
WHERE coalesce(t.dateField, '2000-01-01') <= '2017-08-19'::date;
I'm not sure why you would want to coalesce a "dateField" column to a date. Seems like it already should be a date.
You can also express this as:
WHERE t.dateField <= '2017-09-19' OR t.dateField IS NULL
If you want to convert a column in the format DD/MM/YYYY to a date, then use to_date():
WHERE to_date(t.dateField, 'DD/MM/YYYY') <= '2017-09-19' OR t.dateField IS NULL
As proposed by GordonLinoff you can skip not valid values from casting
SELECT *
FROM a_table AS t
WHERE t.dateField IS NULL
OR dateField = ''
OR cast(t.datefield as date) < cast('19/08/2017' as date)
I have a table TEST with a DATETIME field, like this:
ID NAME DATE
1 TESTING 2014-03-19 20:05:20.000
What I need a query returning this row and every row with date 03/19/2014, no matter what the time is. I tried using
select * from test where date = '03/19/2014';
But it returns no rows. The only way to make it work that I found is to also provide the time portion of the date:
select * from test where date = '03/19/2014 20:03:02.000';
use range, or DateDiff function
select * from test
where date between '03/19/2014' and '03/19/2014 23:59:59'
or
select * from test
where datediff(day, date, '03/19/2014') = 0
Other options are:
If you have control over the database schema, and you don't need the
time data, take it out.
or, if you must keep it, add a computed column attribute that has the time portion of the date value stripped off...
Alter table Test
Add DateOnly As
DateAdd(day, datediff(day, 0, date), 0)
or, in more recent versions of SQL Server...
Alter table Test
Add DateOnly As
Cast(DateAdd(day, datediff(day, 0, date), 0) as Date)
then, you can write your query as simply:
select * from test
where DateOnly = '03/19/2014'
Simple answer;
select * from test where cast ([date] as date) = '03/19/2014';
I am using MySQL 5.6 and there is a DATE function to extract only the date part from date time. So the simple solution to the question is -
select * from test where DATE(date) = '2014-03-19';
http://dev.mysql.com/doc/refman/5.6/en/date-and-time-functions.html
This works for me for MS SQL server:
select * from test
where
year(date) = 2015
and month(date) = 10
and day(date)= 28 ;
select * from test
where date between '03/19/2014' and '03/19/2014 23:59:59'
This is a realy bad answer. For two reasons.
1.
What happens with times like 23.59.59.700 etc.
There are times larger than 23:59:59 and the next day.
2.
The behaviour depends on the datatype.
The query behaves differently for datetime/date/datetime2 types.
Testing with 23:59:59.999 makes it even worse because depending on the datetype you get different roundings.
select convert (varchar(40),convert(date , '2014-03-19 23:59:59.999'))
select convert (varchar(40),convert(datetime , '2014-03-19 23:59:59.999'))
select convert (varchar(40),convert(datetime2 , '2014-03-19 23:59:59.999'))
-- For date the value is 'chopped'.
-- For datetime the value is rounded up to the next date. (Nearest value).
-- For datetime2 the value is precise.
use this
select * from TableName where DateTimeField > date() and DateTimeField < date() + 1
Try this
select * from test where Convert(varchar, date,111)= '03/19/2014'
you can try this
select * from test where DATEADD(dd, 0, DATEDIFF(dd, 0, date)) = '03/19/2014';
There is a problem with dates and languages and the way to avoid it is asking for dates with this format YYYYMMDD.
This way below should be the fastest according to the link below. I checked in SQL Server 2012 and I agree with the link.
select * from test where date >= '20141903' AND date < DATEADD(DAY, 1, '20141903');
Bad habits to kick : mis-handling date / range queries
You can use this approach which truncates the time part:
select * from test
where convert(datetime,'03/19/2014',102) = DATEADD(dd, DATEDIFF(dd, 0, date), 0)
-- Reverse the date format
-- this false:
select * from test where date = '28/10/2015'
-- this true:
select * from test where date = '2015/10/28'
Simply use this in your WHERE clause.
The "SubmitDate" portion below is the column name, so insert your own.
This will return only the "Year" portion of the results, omitting the mins etc.
Where datepart(year, SubmitDate) = '2017'
select *, cast ([col1] as date) <name of the column> from test where date = 'mm/dd/yyyy'
"col1" is name of the column with date and time
<name of the column> here you can change name as desired
select *
from invoice
where TRUNC(created_date) <=TRUNC(to_date('04-MAR-18 15:00:00','dd-mon-yy hh24:mi:ss'));
Test this query.
SELECT *,DATE(chat_reg_date) AS is_date,TIME(chat_reg_time) AS is_time FROM chat WHERE chat_inbox_key='$chat_key'
ORDER BY is_date DESC, is_time DESC
select * from invoice where TRANS_DATE_D>= to_date ('20170831115959','YYYYMMDDHH24MISS')
and TRANS_DATE_D<= to_date ('20171031115959','YYYYMMDDHH24MISS');
SELECT * FROM test where DATEPART(year,[TIMESTAMP]) = '2018' and DATEPART(day,[TIMESTAMP]) = '16' and DATEPART(month,[TIMESTAMP]) = '11'
use trunc(column).
select * from test t where trunc(t.date) = TO_DATE('2018/06/08', 'YYYY/MM/DD')
I have a column in my database called "begin_date".
I am trying to select records where the begin_date are greater than a specific date. I put
select * from Table_Name
where begin_date >= '1/1/2014'
However, it returns error message "String to date conversion error".
I am not sure how to modify the query to make it work?
Thanks!
Try using ISO (8601) standard date formats:
select *
from Table_Name
where begin_date >= '2014-01-01';
select *
from table
where data >= '01/01/2014'
I have a table as
NUM | TDATE
1 | 200712
2 | 200708
3 | 200704
4 | 20081210
where mytable is created as
mytable
(
num int,
tdate char(8) -- legacy
);
The format of tdate is YYYYMMDD.. sometimes the date part is optional.
So a date such as "200712" can be interpreted as 2007-12-01.
I want to write query such that i can treat tdate as a Date column and apply date comparison.
like
select num, tdate from mytable where tdate
between '2007-12-31 00:00:00' and '2007-05-01 00:00:00'
So far i tried this
select num, tdate,
CAST(LEFT(tdate,6)
+ COALESCE(NULLIF(SUBSTRING(CAST(tdate AS VARCHAR(8)),7,8),''),'01') AS Date)
from mytable
SQL Fiddle
How can I use the above converted date (3rd column ) for comparison? (needs a join?)
Also is there a better way to do this?
Edit: I have no control over the table scheme for now.. we have suggested the change to the DB team..for now have to stick with char(8) .
I think this a better way to get your fixed date:
SELECT CAST(LEFT(RTRIM(tdate) + '01',8) AS DATE)
You can create a subquery/cte with the date cast properly:
;WITH cte AS (select num, tdate,CAST(LEFT(RTRIM(tdate)+ '01',8) AS DATE)'FixedDate'
from mytable )
select num, FixedDate
from cte
where FixedDate
between '2007-12-31' and '2007-05-01'
Or you can just use your fixed date in the query directly:
select num, tdate
from mytable
where CAST(LEFT(RTRIM(tdate)+ '01',8) AS DATE) between '2007-12-31' and '2007-05-01'
Ideally you would add the fixed date field to your table so that queries can benefit from indexing the date.
Note: Be wary of BETWEEN with DATETIME as the time portion can result in undesired results if you really only care about the DATE portion.
'2007-12-31 00:00:00' > '2007-05-01 00:00:00', so your BETWEEN clause will never return any records.
This will work, with a subquery, and with the dates flipped:
select num, tdate, formattedDate
from
(
select num, tdate
,
CAST(LEFT(tdate,6) + COALESCE(NULLIF(SUBSTRING(CAST(tdate AS VARCHAR(8)),7,8),''),'01') AS Date) as formattedDate
from mytable
) a
where formattedDate between '2007-05-01 00:00:00' and '2007-12-31 00:00:00'
sqlFiddle here
I think you should avoid storing date in string type fields. If that is something you have to live with try following solution.
Since you are having yyyymmdd or yyyymm format you can first get them all in yyyymmdd format which is Culture independent ISO format and then use style 112 to convert into Date for comparison:
--Culture independent solution
;with cte as (
select num, tdate,
convert(date,left(rtrim(tdate) + '01',8),112) mydate --yyyymmdd format
from mytable
)
select num,tdate,mydate
from cte
where mydate between convert(date,'20071231',112) and --Values are in yyyymmdd format
convert(date,'20070501',112)
Yet another way to turn your string values into dates would be to use REPLACE:
SELECT num, tdate
FROM mytable
WHERE CAST(REPLACE(tdate, ' ', '01') AS date) BETWEEN #date1 AND #date2
;
If you really want to both return the converted date value and use it for filtering, you can employ CROSS APPLY to avoid repeating the logic:
SELECT t.num, t.tdate, x.date
FROM mytable AS t
CROSS APPLY (SELECT CAST(REPLACE(t.tdate, ' ', '01') AS date)) AS x (date)
WHERE x.date BETWEEN #date1 AND #date2
;
This method assumes that your char(8) strings are formatted as either YYYYMMDD or YYYYMM, although the method will work without any changes if you decide to start using values formatted as just YYYY in addition to the other two formats (to imply the beginning of a year, just like a YYYYMM implies the beginning of a month).
with date_cte(num,date)as
(select num,CAST(LEFT(tdate,6)
+ COALESCE(NULLIF(SUBSTRING(CAST(tdate AS VARCHAR(8)),7,8),''),'01') AS Date)
from mytable)
select t1.num, t1.tdate,t2.date
from mytable t1 join date_cte t2 on t1.num=t2.num
where t2.date
between '2007-12-31 00:00:00' and '2007-05-01 00:00:00'
I don't have the time to test right now, but something like this may work...
select num, tdate
from mytable
WHERE CAST(LEFT(tdate,6)
+ COALESCE(NULLIF(SUBSTRING(CAST(tdate AS VARCHAR(8)),7,8),''),'01') AS Date) BETWEEN CAST('2007-12-31 00:00:00' as smalldatetime) and CAST('2007-05-01 00:00:00' as smalldatetime)
My proposal would be to add a date field to your table. If your table is regularly updated, fill it from the legacy field through a stored proc on a regular schedule (either trigger or job).
You'll then be able to use the date as ... a date, without all these tricks, turnarounds, and other approximations which are all potential source for confusion, mistakes and questionable results.
Can you please help me in solving this problem. I am trying to order the results of an SQL query by date, but I'm not getting the results I need.
The query I'm using is:
SELECT date FROM tbemp ORDER BY date ASC
Results are:
01/02/2009
03/01/2009
04/06/2009
05/03/2009
06/12/2008
07/02/2009
Results should be:
06/12/2008
03/01/2009
01/02/2009
07/02/2009
I need to select the date in the format above.
Your help is much appreciated.
It seems that your date column is not of type datetime but varchar. You have to convert it to datetime when sorting:
select date
from tbemp
order by convert(datetime, date, 103) ASC
style 103 = dd/MM/yyyy (msdn)
It sounds to me like your column isn't a date column but a text column (varchar/nvarchar etc). You should store it in the database as a date, not a string.
If you have to store it as a string for some reason, store it in a sortable format e.g. yyyy/MM/dd.
As najmeddine shows, you could convert the column on every access, but I would try very hard not to do that. It will make the database do a lot more work - it won't be able to keep appropriate indexes etc. Whenever possible, store the data in a type appropriate to the data itself.
Unsure what dbms you're using however I'd do it this way in Microsoft SQL:
select [date]
from tbemp
order by cast([date] as datetime) asc
this works for me:
SELECT datefield
FROM myTable
ORDER BY CONVERT(DATE, datefield) ASC
Following answer may help you
perform your date ordering by your date identifier but use to_char() function in select clause and use some other identifier in select clause for date
e.g.
SELECT TO_CHAR(DISPDATE1,'DD/MM/YYYY') AS DISPDATE,
SUM(APPLCOUNT) AS APPLIED,
SUM(CONFCOUNT) AS CONFIRMED
FROM
(
SELECT COUNT(ID) AS APPLCOUNT,
0 AS CONFCOUNT,
STUDENT.APPLIED_ON AS DISPDATE1
FROM STUDENT
WHERE STUDENT.ID = P_ID
GROUP BY STUDENT.APPLIED_ON
UNION
SELECT 0 AS APPLCOUNT,
COUNT(ID) AS CONFCOUNT,
STUDENT.CONFIRMED_ON AS DISPDATE1
FROM STUDENT
WHERE STUDENT.ID = P_ID
GROUP BY STUDENT.CONFIRMED_ON
)
GROUP BY DISPDATE1
ORDER BY DISPDATE1;
SELECT CONVERT(char(19), CAST(date AS datetime), 101) as [date]
FROM tbemp
ORDER BY convert(datetime, date, 101) ASC
Try using this this work for me
select * from `table_name` ORDER BY STR_TO_DATE(start_date,"%d-%m-%Y") ASC
where start_date is the field name
I wanted to edit several events in descendant chonologic order, and I just made a :
select
TO_CHAR(startdate,'YYYYMMDD') dateorder,
TO_CHAR(startdate,'DD/MM/YYYY') startdate,
...
from ...
...
order by dateorder desc
and it works for me.
But surely not adapted for every case...
Just hope it'll help someone !
This may help you in mysql, php.
//your date in any format
$date = $this->input->post('txtCouponExpiry');
$day = (int)substr($date, 3, 2);
$month = (int)substr($date, 0, 2);
$year = (int)substr($date, 7, 4);
$unixTimestamp = mktime(0, 0, 0, $year, $day, $month);
// insert it into database
'date'->$unixTimestamp;
//query for selecting order by date ASC or DESC
select * from table order_by date asc;
try this
Order by Convert(datetime,#date) desc
this should work for your date format
order by convert(date, your_column, 104) desc
Casting/Converting can result in out of range exceptions that unfortunately are not always as simple as excluding nulls.
A simple alternative method, which avoids the cast, is:
SELECT date
FROM table
ORDER BY YEAR(date), MONTH(date), DAY(date) ASC;