Prepare for the second stage of testing

exercise 19 exercise 23 exercise 32 exercise 37 exercise 39 exercise 46 exercise 54 exercise 55 exercise 56 exercise 57 exercise 7 exercise 70 exercise 8 exercises EXISTS FLOAT FOREIGN KEY FROM FULL JOIN GROUP BY grouping Guadalcanal HAVING head ships IDENTITY IN income INFORMATION_SCHEMA inner join INSERT INTERSECT IS NOT NULL IS NULL ISNULL join operations laptop launched year LEFT LEFT OUTER JOIN LEN LIKE LTRIM MAX MIN mistakes money MySQL NATURAL JOIN node NOT NOT IN NULL NULLIF number sequences number-sequence generation numbering ON DELETE CASCADE OR Oracle ORDER BY outcome Outcomes outer joins OVER paging Painting PARTITION BY Pass_in_trip PATINDEX PC PIVOT PostgreSQL predicates primary key printer Product Ranking functions recursive CTE renaming columns REPLACE RIGHT RIGHT JOIN ROUND rounding ROW_NUMBER ships sorting SQL Server SQL Server 2012 SQL-92 sql-ex.ru string functions subquery SUBSTRING SUM tables join tips and solutions Torus Transact-SQL Trip TRUNCATE TABLE type conversion UNION UNION ALL UNKNOWN UNPIVOT UPDATE varchar WHERE window functions WITH XML XPath XQuery