Oracle数据库查询与SQL函数-第二章总览

Chapter 2 of the Oracle Database Design and Implementation Using Oracle presentation introduces the concepts of querying and SQL functions. The main goal of this chapter is to understand how to use the SELECT statement, operators, and functions in SQL*Plus. The SELECT statement is a powerful tool that can be used to create copies of existing tables, insert records from other tables, and display columns with different names using aliases. For example, to create a copy of an existing table, the syntax is: ``` CREATE TABLE <new_table_name> AS SELECT column_names FROM <existing_table_name>; ``` In addition to the SELECT statement, operators and functions play a key role in SQL*Plus. Operators such as arithmetic, comparison, and logical operators can be used to perform operations on data. Functions, on the other hand, are predefined operations that can be used to manipulate data within SQL statements. Overall, Chapter 2 of the Oracle Database Design and Implementation Using Oracle presentation provides a comprehensive overview of querying and SQL functions in Oracle databases. By understanding how to use the SELECT statement, operators, and functions effectively, users can improve their database design and implementation skills.