Chapter 4. Querying and Modifying Data

O BJECTIVES

Retrieve data by using Transact-SQL.

• This objective requires you to know how to access data in different ways, providing for different "looks" into the data with user -friendly views and other reporting methods from the data source.

Filter data by using Transact-SQL.

• You don't often want all the data from the tables. Usually queries want to limit the number of columns and rows displayed from the database. You need to limit and specifically apply conditions over the data that is transmitted to the user interface.

Summarize data by using Transact-SQL.

• A database system needs to generate other information beyond just the data. Arithmetic, statistical analysis, and other operations are needed in a full-service database implementation.

Modify data by using Transact-SQL.

• This objective requires you to also know how to modify existing data in a table using statements such as UPDATE .

O UTLINE

Data Retrieval

The SQL SELECT Statement

FROM Which Table?

The WHERE Clause

ORDER Data

Filtering and Formatting Data

Filtering Data

Formatting the Data

Data Summary

Date Functions

Using Mathematical Functions in T-SQL

Character Functions

System Functions

Making Data Modifications

Inserting Data into Tables

Deleting Data

Updating Data

Apply Your Knowledge

Exercises

Review Questions

Exam Questions

Answers To Review Questions

Answers To Exam Questions

S TUDY S TRATEGIES

• This chapter is one you need to fully understand. Try reading this chapter more than once if needed.

• Be sure to follow the Step by Steps because practical work in this chapter is exceptionally vital . After reading through this chapter, practice creating queries using all the functions and methods mentioned in this chapter.