A、内联接 |
B、自联接(正确答案) |
C、外联接 |
D、左联接 |
A、UNIQUE约束要求数据库中至少存在一行数据,因此必须在创建数据库表之后才能创建,而PRIMARY KEY约束无此限制 |
B、UNIQUE约束允许有空值,而PRIMARY KEY约束不允许有空值 |
C、创建UNIQUE约束后,该数据行允许被更改,而PRIMARY KEY约束的数据行不允许更改 |
D、UNIQUE约束列不能创建外键,而PRIMARY KEY约束可以创建外键引用(正确答案) |
A、Select email from student where email !=null |
B、Select email from student where email not is null |
C、Select email from student where email <> null |
D、Select email from student where email is not null(正确答案) |
A、01053090A(正确答案) |
B、01003090A01 |
C、01053090 |
D、0101A01(正确答案) |
A、SELECT telephone FROM student WHERE telephone LIKE '[86]%0*' |
B、SELECT telephone FROM student WHERE telephone LIKE '(8,6)*0%' |
C、SELECT telephone FROM student WHERE telephone LIKE '[8,6]_0*' |
D、SELECT telephone FROM student WHERE telephone LIKE '[86]_0%'(正确答案) |
A、SELECT phone FROM authors WHERE phone LIKE '4[1,0]%'(正确答案) |
B、SELECT phone FROM authors WHERE phone in '4[^10]%' |
高考网C、SELECT phone FROM authors WHERE phone LIKE '4_[1,0]%' |
D、SELECT phone FROM authors WHERE phone between '41%' and '40%' |
A、SELECT telephone FROM student WHERE telephone LIKE '[86]%0*' |
B、SELECT telephone FROM student WHERE telephone LIKE '(8,6)*0%' |
镜子风水 C、SELECT telephone FROM student WHERE telephone LIKE '[8,6]_0*' |
D、SELECT telephone FROM student WHERE telephone LIKE '[86]_0%'(正确答案) |
A、lect max(score) from grade |
B、lect top 1 score from grade order by score asc(正确答案) |
C、Select min(score) from grade(正确答案) |
D、lect top 1 score from grade order by score desc |
SELECT au_id, title_id,sum(royaltyper) FROM titleauthor GROUP BY title_id, au_id ORDER BY title_id, au_id |
A、该语句会失败率赂秦耶的率 |
B、在结果集中,对每一个不同的au_id的值和title_id的值的组合都会有一行(正确答案) |
C、在结果集中,每一行中au_id的值都不会相同 |
D、在结果集中,每一行中title_id的值都不会相同 |
A、lect * from order where order_price between 1000 and 5000 order by order_price ASC(正确答案) |
B、lect * from order where order_price between 1000 and 5000 order by order_price DESC |
C、lect * from order where 1000<order_price<5000 order by order_price ASC |
D、lect * from order where 1000<order_price<5000 order by order_price DESC |
SELECT DISTINCT 产品.产品名称,产品.单价 FROM 产品(正确答案) |
WHERE(((产品.单价)>(SELECT AVG([单价]) FROM 产品)))深亚麻色 |
ORDER BY产品.单价DESC |
A、“SELECT AVG([单价])FROM产品”是子查询 |
B、“ORDER BY产品.单价 DESC”是指按单价从低到高顺序排列(正确答案) |
C、查询结果显示的是单价大于平均价格的记录 |
D、此查询显示的字段只有“产品名称”和“单价” |
A、外联接查询返回的结果集行数可能大于所有符合联接条件的结果集行数。 |
B、多表联接查询必须使用到JOIN关键字(正确答案) |
C、内联接查询返回的结果是:所有符合联接条件的数据。 |
D、在where子句中指定联接条件可以实现内联接查询。 |
A、Select name as '姓名' from table |
B、Select name as姓名 from table where id =1 |
C、Sleect name = 姓名 from table(正确答案) |
D、Select names姓名 from table |
A、使用group by 进行分组查询 |
B、对分组后的结果进行条件查询必须使用Having子句 |
C、Having子句不能与where子句同时出现在一个lect语句中(正确答案) |
D、在使用分组查询时,在lect列表中只能出现被分组的字段。(正确答案) |
本文发布于:2023-05-14 14:35:31,感谢您对本站的认可!
本文链接:https://www.wtabcd.cn/fanwen/fan/89/897538.html
版权声明:本站内容均来自互联网,仅供演示用,请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系,我们将在24小时内删除。
留言与评论(共有 0 条评论) |