Manipolare dati datetime

Tipi di dati e funzioni in Snowflake

Jake Roach

Field Data Engineer

Estrarre componenti del timestamp

Snowflake offre funzioni per estrarre componenti da un timestamp

SELECT
    <fields>,

    DAY(<1>)  -- Molte altre opzioni!

FROM ...;

<1>: DATE, TIME o TIMESTAMP

DAY
MONTH
YEAR
HOUR
MINUTE
SECOND
DAYNAME
MONTHNAME

Analizzare i timestamp

SELECT
    exam_completed_time,

    YEAR(exam_completed_time) AS y,
    MONTHNAME(exam_completed_time) AS mn,
    DAYNAME(exam_completed_time) AS dn,
    DAY(exam_completed_time) AS d,

    HOUR(exam_completed_time) AS h,
    MINUTE(exam_completed_time) AS m,
    SECOND(exam_completed_time) AS s

FROM STUDENTS.grades;

Analizzare i timestamp

     exam_completed_time  |    y   |   mn  |   dn  |   d  |   h  |   m  |   s 
    --------------------- | ------ | ----- | ----- | ---- | ---- | ---- | ----

     2025-06-25 11:17:02  |  2025  |  Jun  |  Wed  |  25  |  11  |   6  |   2

     2025-06-26 08:49:49  |  2025  |  Jun  |  Thu  |  26  |   8  |  49  |  49
     2025-06-25 09:56:07  |  2025  |  Jun  |  Wed  |  25  |   9  |  56  |   7
     2025-06-24 22:14:27  |  2025  |  Jun  |  Tue  |  24  |  22  |  14  |  27
     2025-06-26 13:36:55  |  2025  |  Jun  |  Thu  |  26  |  13  |  36  |  55
     2025-06-25 16:23:09  |  2025  |  Jun  |  Wed  |  25  |  16  |  23  |   9

                                        ...

DATEDIFF

DATEDIFF calcola l’intervallo tra due date o timestamp

SELECT
    <fields>,


    DATEDIFF(<1>, <2>, <3>)   -- unità, primo timestamp, secondo timestamp


FROM ...;

<1>: Unità di tempo del risultato, ad es. MINUTE, HOUR, DAY, YEAR, WEEK, ecc.

<2>: Timestamp iniziale

<3>: Timestamp finale

Uso di DATEDIFF

Primo TIMESTAMP:   2025-05-12 08:24:08
Secondo TIMESTAMP: 2025-11-13 03:05:46

SELECT 
    DATEDIFF(
        DAY, 
        TO_DATE('2025-05-12 08:24:08'), 
        TO_DATE('2025-11-13 03:05:46')
    )

                                   185 (GIORNI)

DATEADD

SELECT

    -- unità, numero di unità, timestamp
    DATEADD(
        DAY, 
        185, 
        TO_DATE('2025-05-12 08:24:08')
    )

FROM ...;

2025-05-12 08:24:08 + 185 DAYs

         = 2025-11-13 08:24:08

Aggiungi intervalli di tempo a DATE, TIME o TIMESTAMP con DATEADD

<1>: Unità di tempo da aggiungere, ad es. MINUTE, HOUR, DAY, YEAR, WEEK, ecc.

<2>: n. di "unità" da aggiungere al timestamp

<3>: Il timestamp a cui aggiungere

Manipolare una DATE

SELECT
    s_id,
    exam_completed_time AS completed_time,
    exam_due_time AS due_time,

    -- Trova la differenza tra completamento e scadenza
    DATEDIFF(HOUR, exam_completed_time, exam_due_time) AS hours_early,

    -- Data entro cui l'insegnante deve finire la correzione
    DATEADD(WEEK, 1, exam_completed_time) AS grading_due

FROM STUDENTS.grades;

Manipolare una DATE


  s_id  |     completed_time    |        due_time       |  hours_early  |      grading_due
 ------ | --------------------- | --------------------- | ------------- | ---------------------

   919  |  2025-06-25 11:17:02  |  2025-06-26 10:00:00  |       22      |  2025-07-02 11:17:02

   871  |  2025-06-26 08:49:49  |  2025-06-26 10:00:00  |        1      |  2025-07-03 08:49:49
   111  |  2025-06-25 09:56:07  |  2025-06-26 10:00:00  |       24      |  2025-07-02 09:56:07
   465  |  2025-06-24 22:14:27  |  2025-06-26 10:00:00  |       35      |  2025-07-01 22:14:27
   248  |  2025-06-26 13:36:55  |  2025-06-26 10:00:00  |       -3      |  2025-07-23 13:36:55
   767  |  2025-06-25 16:23:09  |  2025-06-26 10:00:00  |       17      |  2025-07-02 16:23:09

                                           ...

Ayo berlatih!

Tipi di dati e funzioni in Snowflake