Mapping subquery and aggregate functions
映射子查询和聚合功能
Instead of using subquery, we join two tables directly.
我们直接将两个表连接在一起，而不再使用子查询。
This statement is represented in the example as subquery S1.
这个语句在示例中表示为子查询s1。
When this statement is executed, the subquery is evaluated first.
当这条语句执行的时候,子查询会先执行.
Each sggrep command can specify both the main query and a subquery.
每一个sggrep命令可以同时指定主查询和子查询。
Often a subquery can substitute a temporary table.
通常一个子查询可以代替一个临时表。
There are not enough columns in the subquery select list.
子查询选择列表中没有足够的列。
A subquery is executed by enclosing it in a set of parentheses.
子查询是被包含在一组圆括号里执行的。
A. a single row subquery can retrieve data from only one table.
单行子查询可以只从一个表中检索数据。
It's important to note that technically, this is not a join, but a subquery.
重要的是要注意在技术上这不是一个联接，而是一个子查询。
Why is the result column of a subquery not using my alias as the column name?
为什么一个查询不使用我的别名为列名的结果列？
The result of that subquery then becomes a value in the WHERE clause expression
它的结果会成为where语句表达式中的一个值。
The result of the scalar subquery first needs to be transferred to the federated server.
首先需要将标量子查询的结果传送到联邦服务器。
Examples of operation merging include view merging and subquery-to-join transformation.
运算合并的例子包括视图合并和子查询-连接(subquery - to - join)转换。
Better error message when using a subquery that contains a reference to non existing property.
当使用的子查询中包含一个不存在的属性时的更友好的错误信息。
In the example, this is represented by the outermost select statement, which USES S1 as a subquery.
在这个示例中，这由最外层的选择语句表示，这个语句将S1用作子查询。
The statement associated with the SHIP1 operator shows the scalar subquery being computed on Oracle.
与SHIP1操作符相关的语句表明该标量子查询在Oracle上计算。
You can use a scalar subquery to select a specific value that will be used in the expression of the WHERE clause.
可以使用标量子查询选择将用于where子句的表达式中的特定值。
To use a table subquery, you need to use an SQL operator to combine the embedded query with a Boolean expression.
要使用表子查询，需要使用SQL操作符将嵌入式查询与布尔表达式组合在一起。
Two types of queries can be used in the WHERE clause of an UPDATE statement: a scalar subquery and a table subquery.
两种查询可以用于update语句的where子句中：标量子查询和表子查询。
The subquery in this statement is absurdly simple, and completely unnecessary, but it does serve to illustrate a point.
这个子查询非常简单，并且完全没有必要，但是它能说明一点。
The SHIP3 operator contains the statement that shows the result of the scalar subquery being bound in as a host variable.
SHIP3操作符包含一个语句，该语句表明标量子查询的结果放在一个主机变量中。
This implies that a subquery SELECT statement can stand alone, and it does not depend on the statement in which it is nested.
这说明子查询SELECT语句可以单独存在，并不依赖于主查询语句。
The last section also describes the ALL, EXISTS, and SOME or ANY predicates, which can be used to express conditions on subquery results.
最后一节还描述了ALL、EXISTS和SOME或ANY 谓词，这些谓词可用于表达子查询结果上的条件。
The query above contains a correlated subquery, since the main query and the subquery are relaying on the same table, the employees table.
以上查询包含一个相关子查询，因为主查询和子查询依靠于同一个表，即employees表。
On the other hand, if you use the EXISTS operator, all rows are modified because at least one of the itemNumber values exists in the table subquery.
另一方面，如果使用EXISTS操作符，则将修改所有行，因为至少有一个itemNumber值存在于表子查询中。
Syntactically, subqueries are enclosed within parentheses. For example, the following SELECT statement contains a simple subquery in its WHERE clause
从语法上来说,子查询被包含在圆括号中.
A scalar subquery is an embedded query that returns a single row that contains a single column — essentially, a single value, which is known as a scalar.
标量子查询是一种嵌入式查询，返回包含单个列的单个行，本质上就是单个值，该值称为标量。
This topic shows two different ways to create a query that orders the source data into groups, and then performs a subquery over each group individually.
本主题演示执行以下任务的两种不同方式：创建一个查询，以便将源数据排序到不同的组中，然后分别对每个组执行子查询。
DB2 can then choose to perform the join or subquery at the database partition where the data is stored, instead of having to move data between database partitions.
于是DB 2就可以在存储数据的数据库分区上执行连接或子查询，而不必在数据库分区之间移动数据。
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