Attach database from YourDbName.mdf without ldf file on SQL Server

• 1 USE Master
  GO
  CREATE DATABASE [YourDbName]
  ON (filename='c:\MSSQL\Data\YourDbName.mdf')
  FOR ATTACH_REBUILD_LOG
  GO
  
• N Migratated from SQL Server 2012 Express to 2016 Express. It runs multiple upgrade steps and creates new LDF log file.
  

References

• https://www.systoolsgroup.com/sql-recovery.html