带有子查询的Oracle PIVOT子句的示例 [英] Example of an Oracle PIVOT clause with subquery

问题描述

Oracle的 PIVOT子句的定义指定可以在IN子句中定义子查询.我能想象的一个虚构的例子就是这个

Oracle's definition of the PIVOT clause specifies that there is a possibility to define a subquery in the IN clause. A fictional example of what I would imagine this to be is this

... PIVOT (AVG(salary) FOR (company) IN (SELECT DISTINCT company FROM companies))

但是，我得到一个ORA-00936: Missing expression错误.不幸的是，来自这个新的PIVOT子句的错误通常是很隐秘的.谁能给我一个很好的示例，说明如何在PIVOT子句的IN子句中使用子查询?

With that, however, I get an ORA-00936: Missing expression error. Unfortunately, errors from this new PIVOT clause are usually rather cryptic. Can anyone give me a good example of how a subquery can be used in the IN clause of the PIVOT clause?

推荐答案

显然，我太懒了，无法阅读文档的结尾...再往下看，文档指出:

Apparently, I was too lazy to read to the end of the documentation... Further down, the documentation states:

子查询子查询仅与XML关键字结合使用.指定子查询时，该子查询找到的所有值都将用于透视. [...]

subquery A subquery is used only in conjunction with the XML keyword. When you specify a subquery, all values found by the subquery are used for pivoting. [...]

这将起作用

PIVOT XML (AVG(salary) FOR (company) IN (SELECT DISTINCT company FROM companies))

查看完整的文档

http://docs.oracle.com/cd/B28359_01/server .111/b28286/statements_10002.htm#CHDFAFIE

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