A basic loop to select all columns from all tables/views in a database, useful with the Database Engine Tuning Advisor on SSMS for a very basic idea of what indices and statistics are missing.

SelectAllTables.sql

DECLARE TOCURSOR CURSOR FOR
SELECT('SELECT * FROM [' + name + '];')
FROM sys.tables
--FROM sys.views
ORDER BY name ASC
DECLARE @query NVARCHAR(MAX)

   OPEN TOCURSOR
      
      FETCH NEXT FROM TOCURSOR INTO 
      @query

	  WHILE @@FETCH_STATUS = 0
	  BEGIN
	  EXEC (@query)
	  FETCH NEXT FROM TOCURSOR INTO
	  @query 
	  END
	CLOSE TOCURSOR
DEALLOCATE TOCURSOR