Convert VARCHAR to DATE in Snowflake

Question

I need to convert my varchar to date.

My varchar looks like this:

event_date
2020-09-20
2021-07-21
2021-01-20
2020-10-08

Here is my attempted solution:

SELECT
  TO_DATE(event_date,'YYYY-MM-DD')
FROM
  database.schema.table

Here is the error I get:

Can't parse ' ' as date with format 'yyyy-mm-dd'

Can anybody help me out? Thanks!

Answer 1

You can use try_to_date(event_date,'YYYY-MM-DD'), it will return NULL (will not fail) if event_date can not be parsed, you can filter and check what exactly it contains:

SELECT
  event_date                           as varchar_date,
  TRY_TO_DATE(event_date,'YYYY-MM-DD') as parsed_date
FROM
  database.schema.table
WHERE TRY_TO_DATE(event_date,'YYYY-MM-DD') IS NULL --filter and check

After checking which formats do you have, you can parse different formats using coalesce:

coalesce(TRY_TO_DATE(event_date,'YYYY-MM-DD'),
         TRY_TO_DATE(event_date,'YYYYMMDD')
         )

Answer 2

Answer was the trim() function for the extra spaces around my varchar. Thanks everyone!