Converting excel integer date format to datetime using QGIS

Question

How to convert Microsoft Excel date format to datetime format using QGIS?

In example: 43089 in MS Excel is 2017年12月20日.

Answer 1

Use this code in field calculator (replace date_field_name_in_MS_Excel_format to your date field name):

to_datetime('1900-01-01 00:00:00') + (to_string("date_field_name_in_MS_Excel_format" - 2) +' day')