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Oracle® 9i SQL Exam Cram™ 2 (Exam 1Z0-007) by Gavin Powell

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Chapter 2. Retrieving Data (SELECT)

Terms You Need to Understand

  • ✓ The SELECT statement

  • ✓ The FROM clause

  • ✓ Query

  • ✓ Column and column list

  • ✓ Schema

  • ✓ Expression

  • ✓ Alias

  • DISTINCT versus ALL

  • NULL

Concepts You Need to Master

  • ✓ What a query is

  • ✓ What an expression is

  • ✓ The difference between a column and an expression

  • ✓ Simple queries

  • ✓ The DUAL table

  • ✓ The effect of NULL values on the result of expressions

  • ✓ The DISTINCT clause

  • ✓ Repeating groups

This chapter jumps straight into the basic syntax of data retrieval using the Oracle SQL SELECT statement, additionally briefly introducing some specifics.

What Is a Query?

A query is a statement interrogating the database and returning information. Most often tables are interrogated and rows from those tables are returned. ...

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