题目内容
（请给出正确答案）
B.SELECT 交易所，avg(单价) FROM stock ORDERS BY 单价
C.SELECT 交易所，avg(单价) FROM stock ORDER BY 交易所
D.SELECT 交易所，avg(单价) FROM stock GROUP BY 交易所
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更多“下面SQL语句中，求每个交易所的平均单价的语句是()。”相关的问题
从下面提供的答案中选出应填入下列英文语句中______内的正确答案。
Application development increasingly means Windows development, and the popularity of visual development tools has(1)in tandem with Windows itself These tools create beautiful windowing(2), and their fast development cycles and easy learning curves make them a good(3)for many types of PC development projects. Today's developers are leveraging these tools and the abundance of heap, powerful PCs to shift the balance of power to the desktop.
As the world moves inexorably toward Windows and other(4)user interfaces, developers can choose from an abundance of(5)oriented tools. Popular examples include Microsoft Corp.'s Visual Basic, Powersoft Corp.'s PowerBuilder, Gupta Technology Corp.'s SQL Windows，and so on.
有如下SQL语句 SELECT交易所,avg(单价)as均价FROM stock； GROUP BY交易所INTO DBT temp 执行该语句后temp表中第2条记录的“均价”字段的内容是_______。
下列SQL语句中，修改表结构的是
A．ALTER
B．CREATE
C．UPDATE
D．INSERT
B.MODIFY_FOR STRUCTURE
C.ALTER TABLE
D.ALTER STRUCTURE
