The document discusses several key concepts in SQL Server including: 1. Data in tables is stored in pages by default in the order records are inserted (natural order). 2. Pages are the basic unit of storage which are grouped into extents of 8 contiguous pages. 3. The ORDER BY clause allows ordering the results of a SELECT statement in ascending or descending order.

1. SQL SERVER
Day 2

2. Natural Order
• When you do a SELECT FROM the table, the
rows will ALWAYS appear in the same order of
insertion
• It’s the “natural” chronologically-entered
order of the rows

3. Natural Order
• Table data is stored as a collection of 8-KB
(8192-byte) pages.
• 8060 bytes for the data on each page.
• A row of data can not span multiple pages.

4. Why Optimizer chooses NCI
• a nonclustered index will have less data in its
pages than a clustered one
• The size of a nonclustered index will be either
equal to or less than the size of a clustered
index… it will never be bigger…

5. Pages and Extents
• The fundamental unit of data storage in SQL
Server is the page.
• Size of a page is 8 KB (96-byte header )
• Header store system information about the page:
• Page Number
• Page Type
• Free pace on the page
• Allocation unit ID

6. Data Page

7. Extents
• Page type: Data, Index, LOB,
ROW_OVERFLOW_DATA etc.
• Extents are the basic unit in which space is
managed.
• Extents are a collection of eight physically
contiguous pages

8. ORDER BY CLAUSE
• ORDER BY order_by_expression [ ASC |
DESC ] [ ,...n ]

9. JOINING OF TABLES
• INNER JOIN
• LEFT OUTER JOIN
• RIGHT OUTER JOIN
• FULL OUTER JOIN
• CROSS APPLY
• OUTER APPLY

10. INNER JOIN

11. LEFT OUTER JOIN

12. RIGHT OUTER JOIN

13. FULL OUTER JOIN