Subqueries

  • Web子查询；次查询

Web Definition

1.
子查询
三、子查询(Subqueries):子查询是在where子句中包含的查询语句，是由系列简单构成的复杂查询。问：谁与smith在同一部门 …
blog.csdn.net|Based on 221 pages
2.
次查询
次查询（Subqueries）　任何数目的次查询可以存在型态的任意层级中，而且次查询可以使用巢状结构，但是却不允许空的次查 …
tw.myblog.yahoo.com|Based on 3 pages

Sample Sentence

Definition:
AllAll,子查询子查询,次查询次查询
Category:AllAll,OralOral,WrittenWritten,TitleTitle,TechnicalTechnical
Source:AllAll,DictionaryDictionary,WebWeb
Difficulty:AllAll,EasyEasy,MiddleMiddle,HardHard
1.
The previous restrictions apply to any subqueries in the FROM clause of the view, just as they apply to the view itself.
上述限制适用于视图的FROM子句中的任何子查询，就像其应用于视图本身一样。
shàng shù xiàn zhì shì yòng yú shì tú de FROM zǐ jù zhōng de rèn hé zǐ chá xún , jiù xiàng qí yìng yòng yú shì tú běn shēn yí yàng 。
msdn2.microsoft.com
2.
The uncorrelated subqueries do not rely on the main query for information; hence they increase the power and flexibility of your main query.
不相关的子查询不依靠主查询来获取信息；因此，它们增加了主查询的能力和灵活性。
bù xiāng guān de zǐ chá xún bù yī kào zhǔ chá xún lái huò qǔ xìn xī ; yīn cǐ , tā men zēng jiā le zhǔ chá xún de néng lì hé líng huó xìng 。
www.ibm.com
3.
Total number of rows processed by the SQL statement. This total does not include rows processed by subqueries of the SQL statement.
sql语句处理的总行数。这个总行数不包括子查询处理的行数。
sql yǔ jù chǔ lǐ de zǒng háng shù 。 zhè ge zǒng háng shù bù bāo kuò zǐ chá xún chǔ lǐ de xíng shù 。
blog.sina.com.cn
4.
Correlated subqueries are often used to test whether relationships exist without regard to cardinality.
相关性查询通常用于测试某种关系是否存在，而不管返回记录集的大小，
xiāng guān xìng chá xún tōng cháng yòng yú cè shì mǒu zhǒng guān xì shì fǒu cún zài , ér bù guǎn fǎn huí jì lù jí de dà xiǎo ,
blog.csdn.net
5.
Note: Transactions containing DML statements with subqueries should use serializable isolation to guarantee consistent read.
如果事务中存在使用了子查询的DML语句，应该使用串行化隔离来保证一致性的读取。
rú guǒ shì wù zhōng cún zài shǐ yòng le zǐ chá xún de DML yǔ jù , yīng gāi shǐ yòng chuàn xíng huà gé lí lái bǎo zhèng yí zhì xìng de dú qǔ 。
www.zw1840.com
6.
Query hints can be specified only in the top-level query, not in subqueries.
只能在顶级查询中指定查询提示，不能在子查询指定。
zhǐ néng zài dǐng jí chá xún zhōng zhǐ dìng chá xún tí shì , bù néng zài zǐ chá xún zhǐ dìng 。
msdn2.microsoft.com
7.
Subqueries used in the subquery comparison test and set membership test both return data values from the subquery table.
在子查询比较测试中使用的子查询和在集合成员资格测试中使用的子查询都从子查询表返回数据值。
zài zǐ chá xún bǐ jiào cè shì zhōng shǐ yòng de zǐ chá xún hé zài jí hé chéng yuán zī gé cè shì zhōng shǐ yòng de zǐ chá xún dōu cóng zǐ chá xún biǎo fǎn huí shù jù zhí 。
www.ianywhere.com
8.
The expressions used in the SET clause can also be subqueries that return only one value.
SET子句中使用的表达式还可以是只返回一个值的子查询。
SET zǐ jù zhōng shǐ yòng de biǎo dá shì hái kě yǐ shì zhǐ fǎn huí yī gè zhí de zǐ chá xún 。
msdn2.microsoft.com
9.
Expressions may be reordered and subqueries may be transformed to improve processing efficiency.
可以对表达式进行重新排序并对子查询进行转换以提高处理效率。
kě yǐ duì biǎo dá shì jìn xíng chóng xīn pái xù bìng duì zi chá xún jìn xíng zhuǎn huàn yǐ tí gāo chǔ lǐ xiào lǜ 。
www.ianywhere.com
10.
Similarly, subqueries impose a certain order of join execution that may not be the most advantageous.
类似地，子查询会使连接按照一定的顺序执行，而这种顺序也许不是最优的。
lèi sì de , zǐ chá xún huì shǐ lián jiē àn zhào yí dìng de shùn xù zhí xíng , ér zhè zhǒng shùn xù yě xǔ bú shì zuì yōu de 。
www.ibm.com