How do I update all values of a column from yyyy to yyyy-yyyy+1 format in postgresql.
Ex: 1942 to 1942-1943
I'd say that this is in general not a good idea, as it doesn't really add any value to the data. It appears you are saving these years in a text format which is already a bit of an issue but it could suit your purposes. Although it won't always sort the years the way you'd expect it to.
It's more reasonable to add this extra data when you're actually serializing the data to your users, at the place it is needed.
I recommend you to change your column data type to Date (date_field1) and create another Date column (date_field2) for this operation,
TO_DATE(date_field1, YYYY);
And then you can update your column as shown below,
UPDATE table SET date_field2 = date_field1 + interval '1 year';
Here is date column manipulation methods, hope it helps.
Related
I am beginner in Backend technology and I am developing one query in Typeorm QueryBuilder + PostgreSQL.
My query is look like this :
But I can't convert my timestamp into following format. Can anyone who has expertise in it, please help me to select all records with timestamp in specific format.
I am suffering this things from last two days but still not find any solution. Actually I want to compare this date format in having clause. so I want to first select that date format then I can use that same method to compare column with current date and previous dates.
i have a field for date with date, month and year.In my visualization, I need date to be displayed in (MON-Year) format.
I switched to data view, created calculated column with
Mon-Year = FORMAT('table'[Date],"YYYY-MM")
Now it's getting displayed as (YEAR and Month number) but I want to change it as month name.
After changes in data view, when I close apply, the column is present but there is no data type visible.
Should I create different calculated fields for year and month separately and then concatenate it?
any help would be appreciated.
If you want month first, then maybe you should specify it that way.
Mon-Year = FORMAT('table'[Date],"MMM-YYYY")
This may be useful for you:
https://learn.microsoft.com/en-us/dax/custom-date-and-time-formats-for-the-format-function
I am newbie to KDB. I have a KDB table which I am querying as:
select[100] from table_name
now this table has got some date columns which have dates stored in this format
yyyy.mm.dd
I wish to query that table and retrieve the date fields in specific format (like mm/dd/yyyy). If this would've been any other RDBMS table this is what i would have done:
select to_date(date_field,'mm/dd/yyyy') from table_name
I need kdb equivalent of above. I've tried my best to go through the kdb docs but unable to find any function / example / syntax to do that.
Thanks in advance!
As Anton said KDB doesn't have an inbuilt way to specify the date format. However you can extract the components of the date individually and rearrange as you wish.
For the example table t with date column:
q)t
date
----------
2008.02.04
2015.01.02
q)update o:{"0"^"/"sv'flip -2 -2 4$'string`mm`dd`year$\:x}date from t
date o
-----------------------
2008.02.04 "02/04/2008"
2015.01.02 "01/02/2015"
From right to left inside the function: we extract the month,day and year components with `mm`dd`year$:x before stringing the result. We then pad the month and day components with a null character (-2 -2 4$') before each and add the "/" formatting ("/"sv'flip). Finally the leading nulls are filled with "0" ("0"^).
Check out this GitHub library for datetime formatting. It supports the excel way of formatting date and time. Though it might not be the right fit for formatting a very large number of objects (but if distinct dates are very less then a keyed table and lj can be used for lookup).
q).dtf.format["mm/dd/yyyy"; 2016.09.23]
"09/23/2016"
q).dtf.format["dd mmmm yyyy"; 2016.09.03] // another example
"03 September 2016"
I don't think KDB has built-in date formatting features.
The most reliable way is to format date by yourself.
For example
t: ([]date: 10?.z.d);
update dateFormatted: {x: "." vs x; x[1],"/",x[2],"/",x[0]} each string date from t
gives
date dateFormatted
------------------------
2012.07.21 "07/21/2012"
2001.05.11 "05/11/2001"
2008.04.25 "04/25/2008"
....
Or, more efficient way to do the same formatting is
update dateFormatted: "/"sv/:("."vs/:string date)[;1 2 0] from t
now qdate is available for datetime parsing and conversion
I am building a map in CartoDB which uses Postgres. I'm simply trying to display my dates as: 10-16-2014 but, haven't been able to because Postgres includes an unneeded timestamp in every date column.
Should I alter the column to remove the timestamp or, is it simply a matter of a (correct) SELECT query? I can SELECT records from a date range no problem with:
SELECT * FROM mytable
WHERE myTableDate >= '2014-01-01' AND myTableDate < '2014-12-31'
However, my dates appear in my CartoDB maps as: 2014-10-16T00:00:00Z and I'm just trying to get the popups on my maps to read: 10-16-2014.
Any help would be appreciated - Thank you!
You are confusing storage with display.
Store a timestamp or date, depending on whethether you need time or not.
If you want formatted output, ask the database for formatted output with to_char, e.g.
SELECT col1, col2, to_char(col3, 'DD-MM-YY'), ... FROM ...;
See the PostgreSQL manual.
There is no way to set a user-specified date output format. Dates are always output in ISO format. If PostgreSQL let you specify other formats without changing the SQL query text it'd really confuse client drivers and applications that expect the date format the protocol specifies and get something entirely different.
You have two basic options.
1 Change the column from a timestamp to a date column.
2 Cast to date in your SQL query (i.e. mytimestamp::date works).
In general if this is a presentation issue, I don't usually think that is a good reason to muck around with the database structure. That's better handled by client-side processing or casting in an SQL query. On the other hand if the issue is a semantic one, then you may want to revisit your database structure.
I have a decimal date field (TDDATR) that is in the YYYYMMDD format.
I would like to create a field that is TDDATR + 30 days but I am unable to.
Using 'Define Results Field' I have tried a few things;
Simply doing this;
TDDATR + 30 DAYS
But it returned this error: Labeled duration not used correctly.
I tried using the DIGITS and SUBSTR commands to create a field in the DDMMYYYY format and then +30 days but got the same error.
Same as above but in the DD/MM/YYYY format - same error.
Using DATE(TDDATR) but all I see is +'s in the field.
Using DATE( ) on the fields created in step 2 and 3 - still get +'s
I've ran out of ideas - any help would be greatly appreciated.
Query/400 lacks a lot of the features that an SQL based interface has.
I'd urge you to consider switching to Query Manager (STRQM) which is a fully SQL based product. You can even convert Query/400 queries to Query Manager queries with the RTVQMQRY command by having the ALWQRYDFN parm set to *YES.
The other option that IBM is pushing is Web Query. Again, fully SQL based and you can convert Query/400 queries into it.
Having said that, the problem is that FLD + 30 DAYS only works when FLD is a DATE data type. Query/400 includes a DATE() function to convert non-date types into date. But it's very limited in that it only works with character fields formatted according to your job defaults. Assuming you're in the US, it'd only work with a character value of '07/01/15'.
You could do a lot of manipulation in Query/400 and end up with a result field that meets DATE()'s requirements. But a better solution would be to create an SQL view over your table and have your numeric date converted into a date data type in the view.
You can find code examples that show how to convert a numeric YYYYMMDD to a actual date data type in the view. However, I'd recommend create a user defined function (UDF) that will do the conversion for you. That will make it much easier to use in the view and to reuse in other places.
If you'd like, there's an open source package called iDate, that includes all the code required for convert to/from date data types.
Download that, install/compile it and your SQL view becomes
select ... idate(TDDATR,'*CCYMD') as TD_DATE
from myfile
The use of days is as follow
Field Expression
CURDATE_30 days(current(date)) + 30
The solution to your problem is: given the field A dec(8,0)
Field Expression
YYYYMMDD_ date(substr(digits(a),5,2)||'/'||
substr(digits(a),7,2)||'/'||
substr(digits(a),3,2))
NEXT_MONTH DAYS(YYYYMMDD_) + 30
Remember to check the date format in your job description. In the example the format is MDY or MM/DD/YY.
More info here
Based on the information here, I created the below 2 fields;
TDDIGI DIGITS(TDDATR)
TDDAT1 SUBSTR(TDDIGI,7,2)||'/'||
SUBSTR(TDDIGI,5,2)||'/'||
SUBSTR(TDDIGI,3,2)
From here I was able to create a date field;
TDDAT2 DATE(TDDAT1)
Which allowed me to perform the necessary calculations.
The format of TDDAT1 is based on your job description which can be found by;
WRKJOB
Option 2
Page down
Date format..: X
Mine was *DMY, so TDDAT1 was formatted based on this.