i have a table like this
|id| date |name|
1 23/11/20 jake
2 01/07/20 jhon
3 23/05/20 blake
4 11/02/20 drake
5 1/03/14 crake
i ran a query like this
WHERE date >= '1/07/20' AND date <= '23/11/20'
i expected a result where i would get only the results between those dates
but i got some results which were from 2014
the data type for the date column is varchar
#note i can not change the datatype
how can i only get dates between the two ?
String-wise comparison is the problem: typically, '10/01/19' (Janurary 10th, 2019) is greater than '01/01/20' (January 1st, 2020), because the former starts with 1, and the later with 0.
You need to turn these strings to dates before you can compare them:
where str_to_date(date, '%d/%m/%y') between '2020-07-01' and '2020-66-23'
This is inefficient, because the entire column needs to be converted before the filtering can happen. I would warmly recommend fixing your data model, and store dates as dates.
Side note: your strings need to be consistently formatted as mm/dd/yy for this to work; if you have varying formats - or strings that do not map to valid dates - then you have a bigger problem than what you have asked here.
Related
I have no experience working with DB2 before and I'm kind of stuck in something. I'm working on a project in SSIS reading from DB2 where I write into a flat file. I need to run the process weekly and get data from past 7 days.
My query works this way:
Select * From Table
Where ServiceDate >= 2200624 - 7
The above query brings data from the past 7 days, but this query don't work for me since I need to execute this process weekly. I need something like this:
Select * From Table
Where ServiceDate >= DATE(CURRENT_DATE - 7 DAY)
The second query throws an error, is there any other way to achieve this? I'm using ODBC source and I was thinking to use a dynamic query in SSIS but I'm not sure how this works in ODBC source, any suggestions or help will be appreciated.
EDIT:
This tables were created a long time ago, so I don't have any information about the data type of these tables.
The actual date 2200624 correspond to 20200624. This is the way that my date shows in the table.
Thanks in advance
For ServiceDate as YYYYMMDD INT:
Select * From Table
Where ServiceDate >= INT(TO_CHAR(CURRENT_DATE - 7 DAY, 'YYYYMMDD'));
If ServiceDate is CHAR(7) or equivalent, and if value 2200624 corresponds to YYYYMMDD date 20200624 as per your edited question, then the following examples might help.
It assumes ServiceDate values beginning with first character 1 are in the 20th century (19xx years), and dates with first character 2 are in the 21st century.
SELECT ... FROM ... WHERE ( TO_DATE(CASE SUBSTR(ServiceDate,1,1) WHEN '1' THEN '19'||SUBSTR(ServiceDate,2,6) WHEN '2' THEN '20'||SUBSTR(ServiceDate,2,6) END,'YYYYMMDD')) >= CURRENT DATE - 7 DAYS
This will perform badly, so don't use that!
An alternative that will perform better is to convert CURRENT DATE - 7 DAYS into a number that matches your storage-format like this:
...WHERE ServiceDate >= '2'||substr(TO_CHAR(CURRENT_DATE - 7 DAY, 'YYYYMMDD'),2,6)
and if ServiceDate is INTEGER column datatype then:
...WHERE ServiceDate >= int('2'||substr(TO_CHAR(CURRENT_DATE - 7 DAY, 'YYYYMMDD'),2,6))
Always state your Db2-server platform (Z/OS, i-series, Linux/Unix/Windows) when asking for help with Db2, because the answer may be different depending on the platform + version of your Db2-server.
SELECT * FROM table WHERE '2016-03-31' > (SELECT MAX(year) from table where bill_id = 'somevalue')
I am using above query to check if 2016-03-31 is greater than all years present in table against bill_id. It is working fine. but is it correct approach to compare dates. dates will always in above format. Is there any need to convert date format for comparison. value 2016-03-31 will change dynamically but it will be always in Y-m-d format
Note : year is column name which contains full date in Y-m-d format like 2016-05-20
You are not comparing dates. You are comparing a string '2016-03-31' with a number, e.g. 2015.
In order to compare, MySQL silently converts the string to number. One would expect this to crash, as '2016-03-31' certainly isn't a number. MySQL, however, reads from left to right and takes from there all that can be considered a number, i.e. '2016'. Well, one could argue that some people put a minus sign at the end of a number, so this should be '2016-', i.e. -2016. Anyway, MySQL stops before the minus sign, gets 2016 and uses this for the comparision.
I don't know if all this is guaranteed to work in the future. I would not rely on this.
What result would you expect anyway? Is the 31st of March 2016 greater than the year 2016? That's a queer question, don't you think?
Try this. But do you really have a column year that stores only year?
SELECT * FROM table WHERE year(STR_TO_DATE('2016-03-31'))
> (SELECT MAX(year) from table where bill_id = 'somevalue')
SELECT * FROM table WHERE YEAR('2016-03-31') > (SELECT MAX(year) from table where bill_id = 'somevalue')
MySQL YEAR() returns the year for a given date or timestamp. The return value is in the range of 1000 to 9999 or 0 for 'zero' date.
i want to do a count of two columns in mysql. One of the columns is a string but another is a date like 06/08/2017 and when i do my query i get 0 results.
SELECT count(*) FROM `castigos` WHERE inicio_normal=05/06/2017 AND cod_emplazamiento=1
I have entries of that data but its dont show me anything. Maybe the type of data in the date is wrong?
What should i do?
Add the date field to your select and group by it. Otherwise mysql extensions doesn't recognize you want to group by the date and will aggregrate all the results into 1 column. And since you are getting 0 count, you're where clause must not be working.
Your date format seems malformed. usually YYYY/MM/DD format (standard format);
or specify a format using SELECT STR_TO_DATE('17/09/2010','%d/%m/%Y');
MySQL retrieves and displays DATE values in 'YYYY-MM-DD' format. The supported range is '1000-01-01' to '9999-12-31'.
the below uses the implicit casting and default date format to convert the string date to a valid date.
SELECT inicio_normal, count(*)
FROM `castigos`
WHERE inicio_normal='2017/05/06'
AND cod_emplazamiento=1
GROUP BY inicio_normal
Otherwise its doing math and comparing that date to the number stored for the date.
Understand dates should be stored in a date datatype and when you query dates you're passing in a string that is being cast to a date datatype for comparison. So you need to use the standard format, or cast your string to a date so the db engine knows how to convert your format to a date.
Try this :
SELECT count(*) FROM `castigos` WHERE inicio_normal="05/06/2017" AND cod_emplazamiento=1 GROUP BY inicio_normal
WHERE inicio_normal=05/06/2017
If you divide 3 by 6 then by 2017 you get a very small value indeed. OTOH if you reformat this as a date (e.g. 20170605, if you gave us a European formatted date - dd/mm/yyyy) then your query will find the rows you showed us.
how to return exactly rows between two dates with timestamps
this code didn't return all row between 01-04 and 07-05
so what is the problem and why it didn't work correctly
and how to select rows between two date with timestamp when i use date
format like this 01-04-2015
SELECT d_send_items.si_id ,
DATE_FORMAT(FROM_UNIXTIME(d_send_items.si_send_date), '%d-%m-%Y')
FROM d_send_items WHERE
DATE_FORMAT(FROM_UNIXTIME(d_send_items.si_send_date), '%d-%m-%Y') BETWEEN '01-04-2015' AND '07-05-2015'
date_format returns a string, so between is using string comparisons to figure out whether the values are between those two you provide.
So, unless your date format is something like yyyy-mm-dd, between is not going to work as you expect.
For example, the date 08-04-2015 is between the two dates 01-04-2015 and 07-05-2015 but the string 08-04-2015 is not between the two strings 01-04-2015 and 07-05-2015, because the most significant portion 08 is beyond the range which terminates at 07....
So you could use:
where
date_format(from_unixtime(d_send_items.si_send_date), '%Y-%m-%d')
between '2015-04-01' and '2015-05-07'
but per-row functions never scale well in relational databases.
If they're proper timestamp fields, I think you can also bypass the conversion and use something like:
where d_send_items.si_send_date >= '01-04-2015'
and d_send_items.si_send_date < '08-05-2015'
(noting the < day following bit for the second conditional since 08-05-2015 is the same as 08-05-2015 00:00:00) assuming MySQL will recognise those date formats as dd-mm-yyyy.
However, even if it doesn't and you have to use some function to turn those string into timestamp values, this is something that would be done once for the whole query rather than (most likely) for every single row.
I have a mySQL query which is outputting decimal fields with a comma.
SELECT Metals.Metal, FORMAT(Fixes.GBPam, 3) AS AM, FORMAT(Fixes.GBPpm, 3) AS PM,
DATE_FORMAT(Fixes.DateTime, '%d-%m-%y') AS Date
FROM Fixes, Metals
WHERE Metals.Id = Fixes.Metals_Id
Fields GBPam and GBPpm are both of type decimal(10,5)
Now I want columns AM and PM to be formatted to 3 decimal places in my sql query - Correct
I want values in the thousands to be formatted as xxxx.xxx and not x,xxx.xxx - Incorrect
Example output from mysql query:
Metal AM PM Date
Gold 1,081.334 NULL 11-09-12
Silver 21.009 NULL 10-09-12
Platinum 995.650 NULL 11-09-12
Palladium 416.700 NULL 11-09-12
Can you see that output for Gold AM is 1,081.334? How can I get it to output 1081.334?
This is a pain in the ass for me because I have to then muck about in PHP to remove the comma. I would prefer to just get mysql to format it correctly.
Just use ROUND, this is a numeric function. FORMAT is a string function
ROUND(Fixes.GBPam, 3)
you can use replace command for this purpose.
REPLACE(Fixes.GBPam,',','')
EDIT:
With respect to your question you could do something like this:
SELECT Metals.Metal, ROUND(REPLACE(Fixes.GBPam,',',''),3) AS AM,
ROUND(REPLACE(Fixes.GBPpm,',',''),3) AS PM,
DATE_FORMAT(Fixes.DateTime, '%d-%m-%y') AS Date
FROM Fixes, Metals
WHERE Metals.Id = Fixes.Metals_Id
Use replace function. Whether the field is integer or varchar, it will work.
select replace(Fixes.GBPam,',','.');