I have a star schema database with an Hour-Dimension (Time-dimension), with the following columns in it:
ID, ON_HOUR, ON_DAY, IN_MONTH, IN_YEAR
I then query the database, and I want to find all entries within an interval of given dates, based on this Hour-Dimension.
However comparing the ON_DAY attribute with the interval days and so on with IN_MONTH and IN_YEAR, I can often reach a case where I receive no data, if the interval spans over several months. Thus I need to convert these values to a timestamp, however I am querying into the database, so how do I compare my given timestamps with the time data properly? I do not have a stored DATE nor TIMESTAMP in the database - should I change this?
Right now, my best bet is something like this:
to_timestamp('H.IN_YEAR-H.IN_MONTH-H.ON_DAY H.ON_HOUR:00:00', 'YYYY-MM-DD hh24:mi:ss')
This does not seem to work however, and it also looks dodgy, so I didn't really expect it to...
What is the best way to get the entries within my given interval of dates?
You appear to be passing a literal string into the timestamp function - you need to pass in the values as a concatenated string using the concat function. Try the below code snippet
(H.IN_YEAR||H-IN_MONTH||H.ON_DAY||H.ON_HOUR,'YYYMMDDHH24')
Related
I'm working on creating a view to convert some values that we get coming in for dates/times. (I've figured out the times already.) In this table, dates come in the format of "Days after 12-31-1840." I'm trying to create a view that shows the actual dates/times rather than in this format. This is what I have so far:
CASE WHEN UPPER(FLWSHT_MEAS_NM) LIKE '%DATE' THEN TO_CHAR(DATE '1840-12-31' + INTERVAL ACUTE_MEASURE_VALUE DAY)
I know that this is the correct syntax for adding dates, because I'm able to get the view working with this instead:
CASE WHEN UPPER(FLWSHT_MEAS_NM) LIKE '%DATE' THEN TO_CHAR(DATE '1840-12-31' + INTERVAL '30' DAY)
My question is, how do I add a specific number of days based on the ACUTE_MEASURE_VALUE field? I'm not able to run the code to get a runtime error as it's coming up as a syntax error.
From the Teradata documentation:
Teradata SQL extends the ANSI SQL:2011 standard to allow the operations of adding or subtracting a number of days from an ANSI DATE value. Teradata SQL treats the number as an INTERVAL DAY value.
I'm assuming your field ACUTE_MEASURE_VALUE is already in your table and is an integer. The words INTERVAL and DAY are part of the specification of interval constants - this is a variable and syntactically you don't use those keywords.
...TO_CHAR(DATE '1840-12-31' + ACUTE_MEASURE_VALUE)...
Just drop the INTERVAL keyword and the DAY keyword and it should work.
By the way, why are you using To_Char() in this? By transforming it into a character string it preempts anyone using this view from performing calculations on this date. If you leave the view in DATE format then any subsequent Select from this view has a lot more flexibility in manipulating this data field.
I need to store a date on MM/YYYY format (without the day) on PostgreSQL.
Is that possible?
I don't want to just pick a day and store the day as well because that would be an incorrect information.
thanks.
mm/yyyy is not a valid date. The day is part of it, and cannot be removed. One alternative would to store the data in a string datatype instead of date, but I would not recommend that: doing so exposes you to data integrity issues (something like 13/2010, for example, is not a valid date part).
For this reason, I would still recommend using the date datatype. You can just ignore the day when accessing the data, if that's not relevant for you. You can also create a computed column based on the date, that displays the information in the format you want:
create table mytabnle (
...
mydate date,
mystr text geneated always as (to_char(mydate, 'mm/yyyy')) stored
);
can anyone explain me the working of trunc(date) function in oracle.
my query is as below.
select trunc(tran_date) from tablename;
i have not passed any format type.
If i compare the date present in table without having trunc(date) it will not give any output.
and if compare date table with trunc(date) it will give me proper ouptut.
please explain how it is working.
and is there any replacement for trunc function as it is taking too much time.
trunc(tran_date) returns the date portion of the date column with no time component (which is midnight at the start of the day).
Despite its name, the date data type in Oracle includes the time. This is even more confusing because you sometimes do not see the time in the result set (depending on how you access the data).
The dates that you are comparing to have no time component. So, the comparison works with trunc(). But the time component on tran_date prevents the comparison from working without trunc().
I am trying to fetch the records which are having all time stamp columns.
I am using the following query to fetch the products that are created between the final date and (final date - 30) days, i.e products created during the last 30 days that fall in the 'final date' range.
I have products that are created on 30-OCT-2014. For the same products, the initiated date is 12-NOV-2014. However they are not being fetched when I using the below query.
SELECT A.ROW_ID,
A.PROD_NAME
FROM PROD A,
PROD_REL B
WHERE A.ROW_ID = B.PAR_ROW_ID
AND TO_DATE(A.CREATED_DT,'YYYY-MM-DD') BETWEEN (TO_DATE(B.FINAL_DATE,'YYYY-MM-DD') - 30)
AND (TO_DATE(B.FINAL_DATE,'YYYY-MM-DD'));
So, could you please let me know if I am missing something?
Here is a link to a SQLFiddle that demonstrates the problem.
… or just fix your format string TO_DATE(A.CREATED,'DD-MON-YYYY')
SQL Fiddle
Storing dates as DATE, is , of course, always a good starting point.
Since your data types are all dates, there is no need to use to_date. It's harmful, in fact, since to_date doesn't take a date as a parameter. Oracle has to do an implicit conversion from a date to a string, using your session's NLS_DATE_FORMAT which gets passed in to to_date and converted back to a date using the explicit format mask you specified. If the two conversions aren't using the same format mask, bad things happen.
Your WHERE clause just needs to be
AND a.created_dt BETWEEN b.final_date - 30
AND b.final_date
If I make that change, your SQLFiddle returns two rows
I am querying a SQLite database table as follows:
SELECT MAX(Date) from Intra360 WHERE Date <= "05/04/2013 00:00"
The right record in return should be the number 47, i.e. 04/04/2013 23:00:
However, the execution of this statement returns a different value:
I confess I know almost nothing about SQL, but this outcome is strange. Where am I being wrong?
NOTE "Intra360" is the name of the table and the field containing the dates is called "Date"
ADDITIONAL NOTE what I need is the closest available date to a user input. It is a Python program which is making some analysis but when the user inputs the dates is not necessarily true they will exist in the database. So I'm just trying to re-select them in a way that the proper SQL statement that will load the data to be used in the analysis won't fail execution because of the missing record. So "05/04/2013 00:00" is the user input, and the query should be done hence starting from 04/04/2013 (and not definetely 04/06/2013).
The comparisons are performed on strings with alphabetical ordering, not on datetime stamps with chronological ordering.
Store your datetimes in a format that compares the way you want. For example, unix epoch timestamps and ISO 8601 yyyy-MM-dd'T'HH:mm:ss datetimes have this property.
If you cannot influence how the data is stored, you can use substr() to mangle the timestamps in SQL. See e.g. Sqlite convert string to date for more.