postgresql中的to_date函數如何工作？

Question

select to_date('20170202','YYYYMMDD'); 

回報：

2017-02-02 

但是當我做：

select to_date('20172202','YYYYMMDD'); 

輸出爲：

2018-10-04 

月份時是錯的，爲什麼不返回一個錯誤如在甲骨文？

Answer 1

我覺得這裏是一個原因，這不會導致一個錯誤：

to_timestamp and to_date exist to handle input formats that cannot be converted by simple casting. These functions interpret input liberally, with minimal error checking. While they produce valid output, the conversion can yield unexpected results. For example, input to these functions is not restricted by normal ranges, thus to_date('20096040','YYYYMMDD') returns 2014-01-17 rather than causing an error. Casting does not have this behavior.

https://www.postgresql.org/docs/9.6/static/functions-formatting.html

Answer 2

我有什麼，我想/ 我使用的TO_CHAR，而不是TO_DATE答案我把fisrt參數轉換成日期..

select to_char(DATE '20162202,'YYYYMMDD') into datResult ; 

所以我現在可以有一個錯誤..

感謝您的幫助大家