How do I round up a date? - sql-server

Question

I have a table that contains the contract information for our customers. I need to round up the contract maturity date to a certain day of the month depending on the contract date itself. For example, if the contract date is 01-05-2016 I need to round it up to 01-10-2016. If the contract date is 01-11-2016 I need to round it up to 01-20-2016. And finally, if the contract date is 01-21-2016 I need to round it up to 01-30-2016. These round up dates match our billing cycles and I need all of our contracts to fall within one of these billing cycles. All dates are a DATETIME data type. Any help would be appreciated.

Answer 1

Maybe something like this?
DECLARE #testData TABLE(TestDate DATE);
INSERT INTO #testData VALUES({d'2016-02-05'}),({d'2016-02-12'}),({d'2016-02-21'});
SELECT TestDate
,CASE WHEN DAY(TestDate) BEtWEEN 1 AND 10 THEN 1
WHEN DAY(TestDate) BEtWEEN 11 AND 20 THEN 2
ELSE 3 END AS BillingCycle
,CASE WHEN DAY(TestDate) BEtWEEN 1 AND 10 THEN CAST(CAST(YEAR(TestDate) AS CHAR(4))+REPLACE(STR(MONTH(TestDate),2),' ','0')+'01' AS DATE)
WHEN DAY(TestDate) BEtWEEN 11 AND 20 THEN CAST(CAST(YEAR(TestDate) AS CHAR(4))+REPLACE(STR(MONTH(TestDate),2),' ','0') +'11' AS DATE)
ELSE CAST(CAST(YEAR(TestDate) AS CHAR(4))+REPLACE(STR(MONTH(TestDate),2),' ','0')+'28' AS DATE) END AS BillingCycleDate
FROM #testData
The result:
TestDate BillingCycle BillingCycleDate
2016-02-05 1 2016-02-01
2016-02-12 2 2016-02-11
2016-02-21 3 2016-02-28

Answer 2

You would do much better to avoid casting dates from strings. The long way is something like this though I'm sure it could be shortened and obfuscated. You did not specify what to do with dates after the 28th though:
dateadd(
day,
case day(contract_dt)
when 1 then 9
when 2 then 8
...
when 10 then 0
when 11 then 9
when 12 then 8
...
when 20 then 0
when 21 then 7
when 22 then 6
...
when 28 then 0
when 29 then -1
when 30 then -2
when 31 then -3
end,
contract_dt
)
Here is one of the more compact forms I alluded to:
dateadd(day, case
when day(contract_dt) <= 20
then 10 - day(contract_dt) % 10
else 28 - day(contract_dt)
end, contract_dt)
EDIT: I presume based on your acceptance of the other answer that you want to fall back to the 28th for the outliers and so I edited the above accordingly.