Forum Discussion
Cannot change data type to date
Please post some sample data for us to assist. The answer to you question will be hidden in the data you are working with.
Ok, lets start with some basics then. How is your date stored in your source dataset? Are they stored as strings, or as numbers in the 'Days since 31/12/1899' format?
Check for a pattern on what dates were changed fine and what dates failed. For example, did dates where the "Day" component was 12 or less convert correctly, but dates after the 13th fail? If so, your dates are being classified as the opposite format to what you are expecting (i.e. DD/MM/YYYY vs MM/DD/YYYY).
Are all if your dates just dates, or as some of them DateTimes?
One option is to format your dates as in the source, or part of the transformation YYYY-MM-DD.
my problem fixed by this solution, https://community.powerbi.com/t5/Desktop/Date-Hierarchy-falls-to-appear-when-joining-on-the-date/td-p/257605 , thank you for help