Converting 'date' stored as integer (number of days since 1 Jan 1970) in Avro to Snowflake 'date' type - snowflake-cloud-data-platform

Question

I've a requirement to migrate data from some on-premise databases to the cloud. Some of the data in the tables is stored as 'date' in format yyyy-mm-dd.
We are converting the data stored in the tables into Avro format and then it's copied into Snowflake.
In Avro, date is stored as an integer Avro Date type
When I try to push the data into snowflake, it's unable to convert that integer back into date. I get the following error: 'Failed to case VARIANT 13707 to date'
where 13707 is number of days since Jan 1 1970
Thanks!

Answer 1

You need to calculate the date value based on the variant value. You can use DATEADD for this purpose:
https://docs.snowflake.com/en/sql-reference/functions/dateadd.html
create table avro_test ( x date );
insert into avro_test(x)
select dateadd('day',parse_json('13707'),'1970-01-01');
select * from avro_test;
+------------+
| X |
+------------+
| 2007-07-13 |
+------------+

Answer 2

If the format of the input parameter is a string that contains an integer:
After the string is converted to an integer, the integer is treated as a number of seconds, milliseconds, microseconds, or nanoseconds after the start of the Unix epoch (1970-01-01 00:00:00.000000000 UTC).
If the integer is less than 31536000000 (the number of milliseconds in a year), then the value is treated as a number of seconds.
If the value is greater than or equal to 31536000000 and less than 31536000000000, then the value is treated as milliseconds.
If the value is greater than or equal to 31536000000000 and less than 31536000000000000, then the value is treated as microseconds.
If the value is greater than or equal to 31536000000000000, then the value is treated as nanoseconds.
If more than one row is evaluated (for example, if the input is the column name of a table that contains more than two rows), the first processed value determines whether all subsequent values are treated as seconds, milliseconds, microseconds, or nanoseconds.
If the first value is greater than or equal to 31536000000, then all values will be treated as milliseconds, even if some remaining values are less than 31536000000. Similar logic applies for microseconds and nanoseconds.