I need help in figuring out the date conversion logic in Snowflake. The documentation isn’t clear enough on this.
In SQL Server, I would try
SELECT CONVERT(DATE, '20200730', 101)
and it gives me ’07/30/2020′.
If I try the following in Snowflake,
to_varchar('20200730'::date, 'mm/dd/yyyy')
it gives me ’08/22/1970′. Why would it give an entire different date? Need help in getting the logic with the correct date.
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Answer
The issue with what you are doing is that you are assuming that Snowflake is converting your string of '20200730'::DATE to 2020-07-03. It’s not. You need to specify your input format of a date. So, 2 options based on your question being a bit vague:
If you have a string in a table and you wish to transform that into a date and then present it back as a formatted string:
SELECT TO_VARCHAR(TO_DATE('20200730','YYYYMMDD'),'MM/DD/YYYY');
--07/30/2020
If the field in the table is already a date, then you just need to apply the TO_VARCHAR() piece directly against that field.
Unlike SQL Server, Snowflake stores date fields in the same format regardless of what you provide it. You need to use the TO_VARCHAR in order to format that date in a different way…or ALTER SESSION SET DATE_OUTPUT_FORMAT will also work.