摘要：
ObjectivesAfter completing this lesson,you should be able to do the following:Describe each data manipulation language(DML) statement.Insert rows into a table.Update rows in a table.Delete rows from a table.Control transactions.Lesson AgendaAdding new rows in a table-INSERT statementChanging data in 阅读全文
摘要：
ObjectivesAfter completing this lesson,you should be able to do the following:Describe set operators.Use a set operator to combine multiple queries into a single query.Control the order of rows returned.Lesson AgendaSet Operators:Types and guidelinesTables used in this lessonUNION and UNION ALL oper 阅读全文
摘要：
ObjectivesAfter completing this lesson,you should be able to do the following:Define subqueries.Describe the types of problems that the subqueries can solve.List the types of subqueries.Write single-row and multiple-row subqueries.single-row:查询结果返回一条记录multiple-row:查询结果返回多条记录Lesson AgendaSubquery:Typ 阅读全文