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[单项选择]Evaluate these two SQL statements:SELECT last_name, salary, hire_dateFROM EMPLOYEES ORDRE BY salary DESC; SELECT last_name, salary, hire_dateFROM EMPOLYEES ORDER BY 2 DESC; What is true about them?()
A. The two statements produce identical results.
B. The second statement returns a syntax error.
C. There is no need to specify DESC because the results are sorted in descending order by default.
D. The two statements can be made to produce identical results by adding a column alias for the salary column in the second SQL statement.
[单项选择] Evaluate these two SQL statements: SELECT last_name, salary , hire_date FROM EMPLOYEES ORDER BY salary DESC; SELECT last_name, salary , hire_date FROM EMPLOYEES ORDER BY 2 DESC; What is true about them?()
A. The two statements produce identical results.
B. The second statement returns a syntax error.
C. There is no need to specify DESC because the results are sorted in descending order by default.
D. The two statements can be made to produce identical results by adding a column alias for the salary column in the second SQL statement.
[单项选择]SQL语句 SELECT部门名称 FROM部门表WHERE部门号IN(SELECT部门号FROM 商品表 WHERE 单价 BETWEEN 420 AND 1000)查询结果是
A. 家用电器部、电话手机部
B. 家用电器部、计算机部
C. 电话手机部、电视录摄像机部
D. 家用电器部、电视录摄像机部
[单项选择]执行如下SQL语句后 SELECT DISTINCT 单价 FROM stock; WHERE 单价=(SELECT min(单价) FROM stock) INTO DBF stock_x 表stock_x中的记录个数是______。
A. 1
B. 2
C. 3
D. 4
[单项选择]有如下SQL SELECT语句 SELECT*FROM kh WHERE 账户金额BETWEEN 30000 AND 60000与该语句等价的是( )。
A. SELECT*FROM kh WHERE 账户金额<=30000.AN账户金额>=60000
B. SELECT*FROM kh WHERE 账户金额<30000.AN账户金额>60000
C. SELECT*FROM kh WHERE 账户金额>=30000.AN账户金额<=60000
D. SELECT*FROM kh WHERE 账户金额>30000.AN账户金额<60000
[单项选择]与SQL语句“SELECT 学号,姓名 FROM student WHERE 成绩 BETWEEN 60 AND 100”等价的是______。
A. SELECT 学号,姓名 FROM student WHERE 成绩<=100.AN成绩>=60
B. SELECT 学号,姓名 FROM student WHERE 成绩<100.AN成绩>60
C. SELECT 学号,姓名 FROM student WHERE 成绩>=100.AN成绩<=60
D. SELECT 学号,姓名 FROM student WHERE 成绩>100.AN成绩<60
[单项选择]执行如下SQL语句后 SELECT DISTINCT 姓名 FROM kh; WHERE 账户金额=50000 INTO DBF kh-x 表中kh-x中的记录个数是( )。
A. 1
B. 2
C. 3
D. 4
[单项选择]SQL语句DELETE FROM学生WHERE年龄>25的功能是( )。
A. 删除学生表
B. 删除学生表中的年龄字段
C. 将学生表中年龄大于25的记录逻辑删除
D. 将学生表中年龄大于25的记录物理删除
[单项选择]有如下SQL语句: SELECT班级名称FROM班级表WHERE NOT EXISTS; (SELECT*FROM学生表WHERE班级号=班级表.班级号) 执行该语句后,班级名称的字段值是
A. 03计算机一班
B. 03计算机二班
C. 03计算机三班
D. 03计算机一班和03计算机二班
[单项选择]有如下SQL语句: SELECT DISTINCT 仓库号 FROM 职工表 WHERE 工资>=ALL; (SELECT 工资 FROM 职工表 WHERE 仓库号="A1") 执行语句后,显示查询到的仓库号有
A. A1
B. A3
C. A1,A2
D. A1,A3
[单项选择]执行如下SQL语句: SELECTDISTINCT工资FROM教师表; WHERE工资=(SELECT MIN(工资)FROM教师表)INTO DBF temp 表temp中的记录个数是
A. 1
B. 2
C. 3
D. 4
[单项选择]执行SQL语句:SELECT sno,grade FROM SC WHERE cno='cl' AND grade<60,则该语句对关系SC执行的操作有()
A. 交(∩)和选择(σ)
B. 选择(σ)和投影(Π)
C. 并(∪)和投影(Π)
D. 选择(σ)和笛卡儿积(×)
[单项选择]有如下SQL语句:
SELECT姓名FROM学生表WHERE学号IN;
(SELECT学号FROM成绩表WHERE成绩>90)
下列哪条命令与该SQL语句等价?
A. 标签
B. 文本框
C. 列表框
D. 选项按钮