Creare date

Analisi delle serie temporali in SQL Server

Maham Faisal Khan

Senior Data Science Content Developer

Cosa imparerai

Lavorare con parti di data
Convertire stringhe in date, incluse date-ora con offset e date non valide
Filtrare, raggruppare e aggregare per periodi
Downsampling dei dati
Aggregazioni su finestre
Upsampling
Calcolare totali progressivi e medie mobili
Trovare sovrapposizioni tra intervalli di date

Creare una data

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

Scomporre una data

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

Analizzare date con parti di data

Funzioni

DATEPART()

SELECT
  DATEPART(YEAR, @dt) AS TheYear;

DATENAME()

SELECT
  DATENAME(MONTH, @dt) AS TheMonth;

Parti

Anno / Mese / Giorno
Giorno dell’anno
Giorno della settimana
Settimana dell’anno
Settimana ISO dell’anno
Minuto / Secondo
Millisecondo / Nanosecondo

Sommare e sottrarre date

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

Confrontare date

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

Arrotondare date

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

Ayo berlatih!

Analisi delle serie temporali in SQL Server