SQL Server Specialist Certificate Program

Maintaining SQL Server 2005

Week 5 – Working with TSQL and Transactions

Performance Tuning

Steve Stedman - Instructor

This Weeks Overview

● Review from Last Week + Homework● TSQL – Transact SQL● Transactions● Performance Tuning● Class Project● Review and Homework

Topics from last week

● Stored Procedures● Functions● Triggers

Homework

● Practice● Assignment● Reading

Preparation

We will be using the AdventureWorks database.

1.TSQL

● Overview● SELECT statements● JOINS (INNER AND OUTER)● Flow Control● Complex Criteria

○ Aggregate Functions, PIVOT / UNPIVOT, Full Text Search

Overview

● What is TSQL○ Transact-SQL○ Microsoft’s Proprietary extension to SQL

● Why use TSQL

SELECT statements

● Used to retrieve data from the database.

SELECT *FROM HumanResources.Employee E

INNER JOINS

● Return only rows that match from both tables

SELECT *FROM HumanResources.Employee EINNER JOIN HumanResources.EmployeeAddress as EA ON E.EmployeeId = EA.EmployeeId

OUTER JOINS

● Returns rows with matching data, as well as rows with nonmatching data

● LEFT OUTER JOIN○ All the rows from the LEFT table

● RIGHT OUTER JOIN○ All the rows from the RIGHT table

● FULL OUTER JOIN○ All the rows from both the LEFT and

RIGHT

Example: LEFT OUTER JOIN

SELECT E.EmployeeID, E.LoginID, EA.* FROM HumanResources.Employee ELEFT OUTER JOIN HumanResources.EmployeeAddress as EA ON E.EmployeeId = EA.EmployeeId

Example: RIGHT OUTER JOIN

SELECT E.EmployeeID, E.LoginID, EA.* FROM HumanResources.Employee ERIGHT OUTER JOIN HumanResources.EmployeeAddress as EA ON E.EmployeeId = EA.EmployeeId

Flow Control

● BEGIN and END● WHILE● BREAK and CONTINUE● GOTO● IF and ELSE● RETURN● WAITFOR

Example: IF and ELSE

IF DATEPART(dw, GETDATE()) = 7 OR DATEPART(dw, GETDATE()) = 1PRINT 'It is the weekend.'ELSEPRINT 'It is a weekday.'

Example: BEGIN and END

IF DATEPART(dw, GETDATE()) = 7 OR DATEPART(dw, GETDATE()) = 1BEGINPRINT 'It is the weekend.'PRINT 'Get some rest!'ENDELSEBEGINPRINT 'It is a weekday.'PRINT 'Get to work!'END

Example: WHILE, BREAK, CONTINUEDECLARE @Counter INTSET @Counter = 10WHILE @Counter > 0BEGINPRINT 'The count is ' + CONVERT(VARCHAR(10), @Counter)SET @Counter = @Counter - 1END

Grouping and Sorting

● ORDER BY - Example SELECT E.LoginID, E.Title, E.ManagerID FROM HumanResources.Employee E ORDER BY E.ManagerID

● GROUP BY - Example SELECT E.ManagerID FROM HumanResources.Employee E GROUP BY E.ManagerID

Aggregate Functions

● AVG● COUNT● MAX● MIN● SUM● STDEV ● VAR

PIVOT / UNPIVOT

● Cross-Tabulation SELECT [0], [1]FROM(SELECT E.SalariedFlag, E.VacationHoursFROM HumanResources.Employee E) AS HPIVOT(AVG(VacationHours)FOR SalariedFlag IN ([0], [1])) AS Pvt

Lab Project – TSQL

● Using the AdventureWorks database, start with the following Query

SELECT * FROM HumanResources.Employee as E1. Modify the output to group by Title, and count the

number of people with each title2. Modify the query to group by the MaritalStatus and

Gender, and count the number of people in each group.

● End of this section. Any Questions?

● 10 Minute Break

1.Transactions

● BEGIN TRANSACTION● COMMIT TRANSACTION● ROLLBACK TRANSACTION● Transaction Sample

BEGIN TRANSACTION

● Starts the transaction● Tracks data changes until COMMIT or

ROLLBACK● Ends only when you COMMIT or

ROLLBACK

Ending a Transaction

● COMMIT TRANSACTION○ Saves Changes

● ROLLBACK TRANSACTION

○ Returns the data to the original state

Transaction Sample

BEGIN TRANSACTION;UPDATE [HumanResources].[Employee] SET [Title] = @Title, [HireDate] = @HireDate WHERE [EmployeeID] = @EmployeeID;

INSERT INTO [HumanResources].[EmployeePayHistory] ([EmployeeID],[RateChangeDate],[Rate])VALUES (@EmployeeID, @RateChangeDate, @Rate);COMMIT TRANSACTION;

See: [HumanResources].[uspUpdateEmployeeHireInfo]

● End of this section. Any Questions?

1.Performance Tuning

● See Other Powerpoint presentation.

● End of this section. Any Questions?

Homework

● Homework for next week○ Work on your class projects

Class Project

● Status Update● Review of research and

experimentation required for the group project.

● Presentations will be week 9

Questions?