在 Snowflake 中将日期转换为数字时间戳

Question

I have a query wherein one of the columns is a DATE type. I'm trying to convert that to the nanosecond representation of the timestamp associated with the date:

Input	Output
2022-07-15	1657843200000000000
2022-07-18	1658102400000000000
2022-07-19	1658188800000000000

I can get a timestamp from a date by doing this:

SELECT TRY_TO_TIMESTAMP(TO_VARCHAR($1))
FROM (
    SELECT DATE($1) FROM VALUES ('2022-07-15'), ('2022-07-18'), ('2022-07-19'))

but using TRY_TO_NUMERIC doesn't work so I'm not sure what to do here.

Answer 1

You can use the datediff function to return the nanoseconds since the start of the Unix epoch, which is 1970-01-01:

with source_data as
(
    select 
    COLUMN1::date as INPUT
    from (values
    ('2022-07-15'),
    ('2022-07-18'),
    ('2022-07-19')
    )
)
select   INPUT
        ,datediff(nanoseconds, '1970-01-01'::date, INPUT) as OUTPUT
from SOURCE_DATA
;

INPUT	OUTPUT
2022-07-15	1657843200000000000
2022-07-18	1658102400000000000
2022-07-19	1658188800000000000