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我正在用SQL编写一个创建视图程序,而我上一次创建视图语句给了我一些麻烦。对于这个观点陈述,我想从哥伦比亚市的所有大学中找回所有的使用者。然后我想使用子查询来获取该人的名字和姓氏的信息。官方的说明如下使用in命令创建一个SQL视图命令
Write a query that returns only the uid value for all universities in the city Columbia. Then use
that query with an IN sub-query expression to retrieve the first and last names for all people that
go to school in Columbias
我现在会后,我写了创建表语句的代码,那么我会后,我将使用的视图语句两个表。我在这里先向您的帮助表示感谢。
CREATE VIEW inn AS
SELECT a.uid
FROM letsdoit.university as a
WHERE b.fname, b.lname IN(SELECT b.fname, b.lname FROM letsdoit.person as b WHERE (a.city = "Columbia"));
表是
Table "letsdoit.university"
Column | Type | Modifiers
-----------------+-----------------------+--------------------------------------
uid | integer | not null default nextval('university) uid_seq'::regclass)
university_name | character varying(50) |
city | character varying(50) |
Table "letsdoit.person"
Column | Type | Modifiers
--------+-----------------------+-----------------------------------------------
pid | integer | not null default nextval('person_pid_seq'::reg class)
uid | integer |
fname | character varying(25) | not null
lname | character varying(25) | not null