Outline Overview of The SQL Query Language ■SQL Data Definition Basic Query Structure of SQL Queries Additional Basic Operations ■Set Operations ▣Null Values Aggregate Functions ■Nested Subqueries Modification of the Database Database System Concepts-7th Edition 3.2 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 3.2 ©Silberschatz, Korth and Sudarshan th Edition Outline ▪ Overview of The SQL Query Language ▪ SQL Data Definition ▪ Basic Query Structure of SQL Queries ▪ Additional Basic Operations ▪ Set Operations ▪ Null Values ▪ Aggregate Functions ▪ Nested Subqueries ▪ Modification of the Database