1 Stroke is the No. 5 cause of death in the U.S., behind heart disease, cancer, chronic lower respiratory disease, and unintentional injuries. 2  About 130,000 Americans die every year from stroke. 3  Every year, 795,000 individuals have a stroke in the United States. 4  Someone in the U.S. dies every 4 minutes from stroke.
A cross join is used when you wish to create combination of every row from two tables. All row combinations are included in the result; this is commonly called cross product join. A common use for a cross join is to create obtain all combinations of items, such as colors and sizes. Note: The series starts with the article Introduction to Database Joins. All the examples for this lesson are based on Microsoft SQL Server Management Studio and the AdventureWorks2012 database.
If you need data from multiple tables in one SELECT query you need to use either subquery or JOIN. Most of times we only join two tables like Employee and Department but some time you may require to join more than two tables and a popular case is joining three tables in SQL.oining three tables in single SQL query can be very tricky if you are not good with concept of SQL Join. SQL Joins have always been tricky not only for new programmers but for many others, who are in programming and SQL for more than 2 to 3 years.