Outer joins may have a negative impact on query performance.
外部连接可能会对查询性能产生负面影响。
The first part of this tutorial presents examples of inner and outer joins.
本教程的第一部分给出了关于内部连接和外部连接的例子。
In fact, there are two kinds of OUTER JOINs, and each has its own advantage and specific use.
实际上，有两种类型的OUTERJOIN，每种类型都有其自己的优点和特定的用途。
Outer joins can be converted to inner joins by augmenting fact tables with default values for foreign keys.
可通过用针对外键的默认值来填充fact表，来将外部连接转换为内部连接。
They can be simple, UNION, or joined sub-queries, including OUTER joins, and can include the ORDER BY clause.
它们可以是简单子查询、UNION或连接（包括OUTER 连接）子查询，并且可以包括ORDERBY 子句。
Lists topics on using joins to query multiple tables, such as how to create outer joins and how to join tables automatically.
列出关于使用联接查询多个表的主题，例如如何创建外部联接和如何自动联接表。
BIRT also provides a special data set called a Joint data set that allows combining existing data sets using inner and outer joins.
BIRT还提供了一个叫做联合数据集(Joint Data Set)的特殊数据集以使用内外连接来整合现存的数据集。
If you want triggers, aggregated functions, outer joins, views, and other SQL features, they are all there (something you won't get from most lightweight relational databases).
如果您想要使用触发器、聚合函数、外部联接、视图以及其他SQL功能，HSQLB都可以满足您的需要(大部分轻量级关系数据库无法做到这一点)。
Because of how nested loop joins work, the second leg (there are four nodes) is executed per outer table record.
因为嵌套循环联接的工作方式，所以每隔一个外部表记录执行第二步(共4个节点)。
Because of how nested loop joins work, the second leg (there are four nodes) is executed per outer table record.
因为嵌套循环联接的工作方式，所以每隔一个外部表记录执行第二步(共4个节点)。
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