How to get Previous Month number and Month before Previous Month number in SQLite,
I am using strftime('%m','now') for getting current month number but not finding anything to extract previous month number, how to do this
You can use the date function to get the previous month:
SELECT strftime('%m', date('now','start of month','-1 month'));
SELECT strftime('%m', date('now','start of month','-2 month'));
It's fairly self explanatory: This uses the date function to get the first day of the current month (to prevent issues on the last days of a month with more days than the previous month), then subtract 1 or 2 months. Then use strftime to pull out just the month number.
SQLite has a modulo operator (%), so if month is the current month number, you can calculate:
previous_month = (month - 2) % 12 + 1
month_before_previous = (month - 3) % 12 + 1
Related
Good morning to all,
I would need your help of the most professional!
In my datastudio I have a column MONTH and I would like to create an automatism, where I can take the column MONTH -1 and based on the previous month, and once done this take into account the column RATING and return the value.
I used this formula but it doesn’t work:
WHEN Month < DATETIME_TRUNC(TODAY(), MONTH) AND Month >= DATETIME_TRUNC(DATETIME_SUB(TODAY(), INTERVAL 1 MONTH), MONTH) THEN 1 "
can you help me?
I would like to take the case Month and then take into account the previous Month and on this basis calculate the rating
I'm looking for a good solution to show the average temperature day by day of the year from a SQLite Database.
In my database, to be sample, I have a date column and a temp column, for each day since 5 years like that.
example
I would like to get, for each day of the year, the average temperature from my database.
I found the request to calculate the average for one day, but I don't how can I do like that for each day
SELECT avg(min) FROM historique WHERE strftime('%m-%d', date )= "04-01";
Could you help me please ?
You must use use GROUP BY:
SELECT strftime('%m-%d', date) day, avg(min)
FROM historique
GROUP BY day
I have current_date in Teradata which 18 DEC 2019
I have to calculate the previous quarter start date and end date from the above current_date.
Input = '2019-12-18'
Output Start Date = '2019-07-01'
Output End Date = '2019-09-30'
You should be able to do this using the TRUNC function, something like:
SELECT
TRUNC(ADD_MONTHS(CURRENT_DATE, -3), 'Q') AS Start_Quarter, -- Previous quarter start
TRUNC(CURRENT_DATE, 'Q') - 1 AS End_Quarter -- Current quarter start date - 1 day
Give it a try and let me know. This assumes the mistake in the manual is still considered a "mistake".
Also, depending on what TD version you're using, you may be able to use built-in functions:
SELECT
TD_QUARTER_BEGIN(CURRENT_DATE) AS Start_Quarter,
TD_QUARTER_END(CURRENT_DATE) AS End_Quarter
Reference
TD Manual
Built-in functions
I have a simple SQL for calculating week number in my reports on SQLite
SELECT STRFTIME('%W', 'date_column')
It was correct for 2009-2012. In 2013 I got always the wrong week number.
For example
SELECT STRFTIME('%W', '2012-02-28')
return '09' and this is correct.
SELECT STRFTIME('%W', '2013-02-28')
return '08' and this is wrong. We have the 9th week.
Is there something in SQLite date time functions that I don't understand? Or is it a bug of SQLite?
CL's answer works fine for OP's definition of "right", which is not quite the same as ISO definition. ISO week numbers are always in the range 1-53 (no week 0), and the last 3 days of a year may fall into Week 1 of the following year, just like the first 3 days may fall into Week 52 or 53 of the preceding year. To take these corner cases into account, you need to do something like:
SELECT
(strftime('%j', date(MyDate, '-3 days', 'weekday 4')) - 1) / 7 + 1 AS ISOWeekNumber
FROM MyTable;
As a side note, SQLite's Date and Time documentation does link to the POSIX strftime man page, which defines %W modifier as:
"week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0."
To convert from SQLite's undocumented week definition (first week is the week with the year's first Monday in it, or the week with 7 January in it) to the ISO week definition (first week is the week with the year's first Tuesday in it, or the week with 4 January in it), we let SQLite compute the week of the year's 4 January. If that is not one, we have to increase the week number:
SELECT strftime('%W', MyDate)
+ (1 - strftime('%W', strftime('%Y', MyDate) || '-01-04'))
FROM MyTable
I'm trying to obtain the current week for date comparison in SQLite.
I have no problem for last month, last year, today, yesterday... but don't find the solution to have the current week.
I tried lot of things like:
SELECT tastings.* FROM tastings
WHERE (DATE(tastings.date) > DATE('now','weekday 1','+ 7 days'))
Can you help me ? Thanks.
This code gives you the week number where the first day of week is monday. It also works well for last and first weeks of the year.
strftime('%W', 'now', 'localtime', 'weekday 0', '-6 days')
I guess you want compare 2 date, Assume you have a table named _testTbl and have 3 column _id INTEGER, _name TEXT, _recordDate TEXT
you want name that record this week
you can use below code:
SELECT * FROM _testTbl
WHERE _recordDate > datetime('now', 'start of day', 'weekday 6', '-7 day')
note that this week start by saturday (sunday 0, monday 1, ..., saturday 7)
this t-sql means:
datetime is a sqlite date and time function.
first parameter is given time: 'now' means the current time.
second parameter take the time to start of day.
third parameter take time to the next weekday number (in this case, saturday).
fourth parameter take time to start of week
What is stored inside the tastings.date column? Note that SQLite does not have “timestamp” type affinity, so probably you store Text (some representation of the date) or integer (julian day, epoch…)
All time and date functions expect a valid time string and convert that time string to another string format. If tastings.date contains a week number then use:
AND cast(tastings.date AS TEXT) = strftime('%W','now')
This helps me to compare the 2 dates using the week of the year.
AND ( strftime('%W', tastings.date) = strftime('%W', 'now') )
Thanks you.