One example : sql can join tables or nest queries 例如: sql可以連接表或嵌套查詢。
Explains how to create subqueries , or nested queries 解釋如何創建子查詢或嵌套查詢。
You can always convert a nested query into an equivalent join 您始終可以將嵌套查詢轉換成等價的連接。
Otherwise , the nested query must be processed for each result of the outer query to ensure elimination of duplicates 否則,為確保消除重復值,必須為外部查詢的每個結果都處理嵌套查詢。
In general , sql 2005 notification supports select queries as well as stored procedures , and supports multiple and nested queries , but does not support aggregate operations such as 總之, sql 2005通知支持select查詢和存儲過程,支持多個查詢和嵌套查詢,但不支持聚合操作(例如