how to convert string to date in big query

Question

tried with below query select parse_date("sting_date", %y-%m-%d) form [project_id:dataset.table]

input value string value = 20150518 expected output date value = 2015-05-18

Tried to parse_date("sting date", %y-%m-%d) in selection query not worked

Answer 1

You need to use an uppercase Y and flip arguments:

SELECT
  PARSE_DATE('%Y%m%d', '20180805') AS date

Answer 2

I think that should be parse_date("%y%m%d", sting_date)

see:parse date