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SQL Server子查询教程和资料

[英]SQL Server sub query tutorial & material

原文 2010-12-04 20:27:31 5 2 sql

I am studying SQL Server and got stuck with the sub query syntax. 我正在研究SQL Server，并陷入了子查询语法中。 Could someone show me some sites, links, where i could study them please? 有人可以告诉我一些网站，链接，请在哪里学习？

2 个解决方案

The subquery is a valuable concept to understand. 子查询是一个有价值的概念。 Creative use of a subquery allows the desired results to be returned in a single T-SQL statement, and helps avoid the use of temporary tables and cursors to solve complicated selection criteria. 创造性地使用子查询可以在单个T-SQL语句中返回所需的结果，并有助于避免使用临时表和游标来解决复杂的选择条件。 In addition, depending on the query, a subquery might improve performance by reducing the number of records that SQL Server needs to process. 此外，根据查询的不同，子查询可以通过减少SQL Server需要处理的记录数来提高性能。

Easy one: 简单的一个：

http://msdn.microsoft.com/en-us/library/ms189575.aspx http://msdn.microsoft.com/en-us/library/ms189575.aspx

Detailed one: 详细一：

http://www.aspfree.com/c/a/MS-SQL-Server/Subqueries-and-Query-Expressions/ http://www.aspfree.com/c/a/MS-SQL-Server/Subqueries-and-Query-Expressions/

Introductory tutorials: 入门教程：

http://beginner-sql-tutorial.com/sql-subquery.htm http://beginner-sql-tutorial.com/sql-subquery.htm

http://onlamp.com/pub/a/onlamp/2001/07/26/aboutSQL.html http://onlamp.com/pub/a/onlamp/2001/07/26/aboutSQL.html