Migrate MySQL to MSSQL with views
Rather unfortunately ... https://www.sqlservercentral.com/articles/20-tips-on-converting-mysql-views-to-ms-sql 


  Although there are many free tools and solutions to migrate MySQL data to MS SQL server, none of them is able to convert views. That's why everybody who wants to migrate complete database have to convert views manually ...


After that they give 20 tips on how to convert the view-declaration so that mssql understands it. Unfortunately this means you have to work view by view .. by hand