Building dates

Time Series Analysis in SQL Server

Maham Faisal Khan

Senior Data Science Content Developer

What you will learn

Working with component date parts
Translating strings to dates, including date-time offsets and invalid dates
Filtering, grouping, and aggregating data by time periods
Downsampling data
Aggregations over windows
Upsampling
Calculating running totals and moving averages
Finding overlap in date ranges

Building a date

SELECT
    GETDATE() AS DateTime_LTz,
    GETUTCDATE() AS DateTime_UTC;

SELECT
    SYSDATETIME() AS DateTime2_LTz
    SYSUTCDATETIME() AS DateTime2_UTC;

Results:

DateTime_LTz	DateTime_UTC	DateTime2_LTz	DateTime2_UTC
2019-03-07 21:21:33.670	2019-03-08 02:21:33.670	2019-03-07 21:21:33.6716402	2019-03-08 02:21:33.6716402

Breaking down a date

DECLARE
    @SomeDate DATETIME2(3) = '2019-03-01 08:17:19.332';

SELECT YEAR(@SomeDate);

SELECT MONTH(@SomeDate);

SELECT DAY(@SomeDate);

YEAR = 2019

MONTH = 3

DAY = 1

Parsing dates with date parts

Functions

DATEPART()

SELECT
  DATEPART(YEAR, @dt) AS TheYear;

DATENAME()

SELECT
  DATENAME(MONTH, @dt) AS TheMonth;

Parts

Year / Month / Day
Day of year
Day of week
Week of year
ISO week of year
Minute / Second
Millisecond / Nanosecond

Adding and subtracting dates

DECLARE
    @SomeTime DATETIME2(7) = '1992-07-14 14:49:36.2294852';

SELECT
    DATEADD(DAY, 1, @SomeTime) AS NextDay,
    DATEADD(DAY, -1, @SomeTime) AS PriorDay;

SELECT
    DATEADD(HOUR, -3, DATEADD(DAY, -4, @SomeTime)) AS Minus4Days3Hours;

NextDay	PriorDay
1992-07-15 14:49:36.2294852	1992-07-13 14:49:36.2294852

Minus4Days3Hours
1992-07-10 11:49:36.2294852

Comparing dates

DECLARE
    @StartTime DATETIME2(7) = '2012-03-01 14:29:36',
    @EndTime DATETIME2(7) = '2012-03-01 18:00:00';

SELECT
    DATEDIFF(SECOND, @StartTime, @EndTime) AS SecondsElapsed,
    DATEDIFF(MINUTE, @StartTime, @EndTime) AS MinutesElapsed,
    DATEDIFF(HOUR, @StartTime, @EndTime) AS HoursElapsed;

SecondsElapsed	MinutesElapsed	HoursElapsed
12624	211	4

Rounding dates

DECLARE @SomeTime DATETIME2(7) = '2017-05-12 16:25:16.2248991';

SELECT
    DATEADD(DAY, DATEDIFF(DAY, 0, @SomeTime), 0) AS RoundedToDay,
    DATEADD(HOUR, DATEDIFF(HOUR, 0, @SomeTime), 0) AS RoundedToHour,
    DATEADD(MINUTE, DATEDIFF(MINUTE, 0, @SomeTime), 0) AS RoundedToMinute;

RoundedToDay          RoundedToHour         RoundedToMinute
2017-05-12 00:00:00   2017-05-12 16:00:00   2017-05-12 16:25:00

Let's practice!

Time Series Analysis in SQL Server