对表的一些基本操作1 Creating a TablesyntaxCREATE TABLE Tablename (column_name type, column_name, type, .....)for exampleCREATE TABLE Employee (names VARCHAR(20),

JOins Jions  a common way to combine table in SQL.1 we use the JOIN keyword and an ON clause.syntax isSELECT columnsFROM table1 JOIN table2ON table1.column1=table2.column1Note th

 1  Noncorrelated SubqueriesA noncorrelated subquery is a subquery that is independent of the outer query. In other words, the subquery could be executed on its own. The following is an example of

今天开始看SQL  打算半个月搞定这本书第一天读书笔记1   SQL Server 2005 comes with some default System databases--master, model, msdb, and tempdbmaster is a database composed of system tables that keeps track of ser

Learn how to write (build) simple SQL query statements in SQL Server 2005 using the SELECT statement. 1 Displaying or Selecting Columns from a TableUsing a SELECT statement, we do not have to di

About Aggregate Function1An aggregate function basically combines multiple rows into a single number. Aggregate functions can be used to count the number of rows, find the sum or average of all