i have MySQL db that contains event's date and 3 ranges, i.e from1-to1, from2-to2, from3-to3
each range has different price, i.e from1-to1 rate1 , from2-to2 rate2, ...
so that's 3 columns for each range: from, to and rate.
i'm trying to find the query that returns the rate for a given month, meaning finds the range that the month is in and returns the rate of that range.
any ideas?
thanks!
If you make an extra table just for the ranges you would keep your schema in normal form and you could easy select the right rate: TABLE range, COLUMNS from, to, rate. With a foreign key linking to your original table. Then you could SELECT rate FROM range WHERE 'date' >= from AND 'date' <= to.
It seems like your data model is not normalized. You should consider morjas suggestion about creating an additional table.
Below is a really ugly query that checks whether a date is in any of the three ranges, and then returns the matching rate.
select case
when date '2010-12-05' between range1_from and range1_to then range1_rate
when date '2010-12-05' between range2_from and range2_to then range2_rate
when date '2010-12-05' between range3_from and range3_to then range3_rate
end as rate
from events
where date '2010-12-05' between range1_from and range1_to
or date '2010-12-05' between range2_from and range2_to
or date '2010-12-05' between range3_from and range3_to;
Related
I have a table that holds 2 columns - location and date.
Each line of location and date marks a day when no operations were performed at that location.
I need a query that will show me the locations that have not been moved at all in the date range.
For example, if I search from the date 1.11.22 to the date 8.11.22, only the locations that have a row in each day should appear (and in fact no transactions were made in them on that day). It is enough that there is one day in which transactions were made (the row with the date in the date range does not appear in the table) so it should not be shown to me in the query.
I tried something like this:
select loc,thedate
from
thetable
where exists(
select 'x' from thetable
where thedate between '2022-11-01' and '2022-11-08'
)
The table is also very heavy and the search is heavy, I wanted to know if this is the most efficient way to search by date range?
I was wondering, in SQL/dbt is there a way to set all dates to be >= another date?
Say I have a 'createdat' date field and a 'updatedat' date field. I use it multiple times in my query (multiple CTEs) as well as other dates. I want to make sure all dates used are less then the last day of last month (i.e. <= last_day(current_date()-30, month)).
Is there a way to set that in the beginning of the query?
This can definitely be done. You'll want to compare the greatest() of a number of columns with whatever date cut-off you want.
Effectively, it would be:
select *
from {{ ref('some_table') }}
where greatest(created_at,updated_at) < date_trunc('month', current_date)
You can obviously add as many columns to that query as you'd like.
N.B.: On some warehouses, greatest returns null if any of the columns in it are null. In that situation, you'll need to coalesce each date with some date placeholder, like '1970-01-01'.
I am struggling with a DAX pattern to allow me to plot an average duration value on a chart.
Here is the problem: My dataset has a field called dtOpened which is a date value describing when something started, and I want to be able to calculate the duration in days since that date.
I then want to be able to create an average duration since that date over a time period.
It is very easy to do when thinking about the value as it is now, but I want to be able to show a chart that describes what that average value would have been over various time periods on the x-axis (month/quarter/year).
The problem that I am facing is that if I create a calculated column to find the current age (NOW() - [dtOpened]), then it always uses the NOW() function - which is no use for historic time spans. Maybe I need a Measure for this, rather than a calculated column, but I cannot work out how to do it.
I have thought about using LASTDATE (rather than NOW) to work out what the last date would be in the filter context of any single month/quarter/year, but if the current month is only half way through, then it would probably need to consider today's date as the value from which to subtract the dtOpened value.
I would appreciate any help or pointers that you can give me!
It looks like you have a table (let's call it Cases) storing your cases with one record per case with fields like the following:
casename, dtOpened, OpenClosedFlag
You should create a date table with on record per day spanning your date range. The date table will have a month ending date field identifying the last day of the month (same for quarter & year). But this will be a disconnected date table. Don't create a relationship between the Date on the Date table and your case open date.
Then use iterative averagex to average the date differences.
Average Duration (days) :=
CALCULATE (
AVERAGEX ( Cases, MAX ( DateTable[Month Ending] ) - Cases[dtopened] ),
FILTER ( Cases, Cases[OpenClosedFlag] = "Open" ),
FILTER ( Cases, Cases[dtopened] <= MAX ( DateTable[Month Ending] ) )
)
Once you plot the measure against your Month you should see the average values represented correctly. You can do something similar for quarter & year.
You're a genius, Rory; Thanks.
In my example, I had a dtClosed field rather than an Opened/Closed flag, so there was one extra piece of filtering to do to test if the Case was closed at that point in time. So my measure ended up looking like this:
Average Duration:=CALCULATE(
AVERAGEX(CasesOnly, MAX(DT[LastDateM]) - CasesOnly[Owner Opened dtOnly]),
FILTER(CasesOnly, OR(ISBLANK(CasesOnly[Owner Resolution dtOnly]),
CasesOnly[Owner Resolution dtOnly] > MAX(DT[LastDateM]))),
FILTER(CasesOnly, CasesOnly[Owner Opened dtOnly] <= MAX(DT[LastDateM]))
)
And to get the chart, I plotted the DT[Date] field on the x-axis.
Thanks very much again.
Here trip 1 involves 2 activity_code in a single day and also concludes in a single day and most other activities are just single day but i have one trip that span over more than one day.
What could be the best possible way to store date range for that column that span more than one days.
Splitting the column into multiple begin date and end date just doesn't make sense as there would be many blank columns?
trip_id(pk,fk) Activity_code(pk,fk) date
1 a1 1st October 2015
1 a2 1st October 2015
2 a3 2nd -5th October 2015
Keep in mind that i need to search the activity_code on basis of month. such as list all the activity code that occur in October ?
Is it possible to insert a range of date in a single column or any other design solution ?
Is there any datatype that can represent the date range in single value ?
PS: oracle 11g e
Store the date ranges as FirstDate/LastDate or FirstDate/Duration.
This allows you to store the values in the native format for dates. Storing dates as strings is a bad, bad idea, because strings don't have all the built-in functionality provided for native date types.
Don't worry about the additional storage for a second date or duration. In fact, the two columns together are probably smaller than storing the value as a string.
Splitting the date into start date and end date would be ideal. Storing dates as strings is not recommended. If you store your dates as strings then there is a possibility of malformed data being stored in the column since a VARCHAR2 column will allow any value. You will have to build strong validations in your script while inserting the data which is unnecessary.
Secondly, you will not be able to perform simple operations like calculating the duration/length of the trip easily if both the start_date and end_date are stored in the same column. If they are stored in different columns it would be as simple as
SELECT trip_id, activity_code, end_date - start_date FROM trips;
I have a table named Sales and a column within it named Date. I'm simply trying to find how many sales were made on a specific date. My intuition was to use something like this:
SELECT COUNT(Date) FROM Sales WHERE Date='2015-04-04'
this should count all sales that were made on that date, but that returns 0. What am I doing wrong?
While it is difficult to be precise without table definitions or an indication of what RDBMS you are using, it is likely that Date is a time/date stamp, and that the result you want would be obtained either by looking for a range from the beginning of the day to the end of the day in your WHERE clause, or by truncating Date down to a date without the time before comparing it to a date.
Try the below once.
select count(*) from <t.n> where date like '2015-04-04%';
When you want to find the count of rows based on a field (Date) You need to Group By over it like this:
SELECT Date, COUNT(*)
FROM Sales
GROUP BY Date
Now you have all count of rows for each Date.
Type and Value of Date is important in the result of the above query.
For example in SQL Server your best try is to convert a DateTime field to varchar and then check it as the result of CONVERT like this:
SELECT COUNT(*)
FROM Sales
WHERE CONVERT(VARCHAR, Date, 111) = '2015/04/04'