（15 ）在 SQL 的 SELECT 语句中，用于实现选择运算的是A ） FOR B ） WHILE C ） IF D ） WHERE

A.SELECT书名,作者,单价 FROM 图书 WHERE(单价＞15 AND 单价＜25)AND(书名LIKE"%计算机%")

B.SELECT书名,作者,单价 FROM 图书 WHERE(单价BETWEEN 15 AND 25)AND(书名="计算机")

C.SELECT书名,作者,单价 FROM 图书 WHERE(单价BETWEEN 15 AND 25)AND(书名LIKE"%计算机%")

D.SELECT书名,作者,单价 FROM 图书 WHERE(单价＞=15 AND ＜=25)AND(书名LIKE"%计算机%")

A.SELECT Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno AND SC.Cno= ‘2’ AND SC.Grade ＞ 90

B.SELECT Student.Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno AND SC.Grade ＞ 90

C.SELECT Sno, Sname FROM Student, SC WHERE SC.Cno= ‘2’ AND SC.Grade ＞ 90

D.SELECT Student.Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno AND SC.Cno= ‘2’ AND SC.Grade ＞ 90

设有 SC(学号 , 课程号 , 成绩 ) 表，下面 SQL 的 SELECT 语句检索成绩高于或等于平均成绩的学生的学号。SETECT 学号 FROM sc WHERE 成绩 ＞= (SELECT 【 15 】 FROM sc)

Evaluate this SQL statement:SELECT e.employee_id, (.15* e.salary) + (.5 * e.commission_pct) + (s.sales amount * (.35 * e.bonus)) AS CALC_VALUEFROM employees e, sales sWHERE e.employee_id = s.emp_id;What will happen if you remove all the parentheses from the calculation？ （）

A. The value displayed in the CALC_VALUE column will be lower.

B. The value displayed in the CALC_VALUE column will be higher.

C. There will be no difference in the value displayed in the CALC_VALUE column.

D. An error will be reported.

A.SELECT sno,sname FROM student WHERE sname LIKE N'张%'

B.SELECT sno,sname FROM student WHERE sname LIKE N'%张%'

C.SELECT sname FROM student WHERE sname = N'张%'

D.SELECT sname FROM student WHERE sname = N'%张%'

A.SELECT*FROMWebsitesWHERE(alexa>15ANDcountry='CN')ORcountry='USA';

B.SELECT*FROMWebsitesWHEREalexa>15AND(country='CN'ORcountry='USA');

C.SELECT*FROMWebsitesWHEREalexa>15ANDcountry='CN'ORcountry='USA';

D.SELECT*FROMWebsitesWHEREalexa>15OR(country='CN'ORcountry='USA');

A.SELECT sno,sname FROM student WHERE sname LIKE N'张%'

B.SELECT sno,sname FROM student WHERE sname LIKE N'%张%'

C.SELECT sname FROM student WHERE sname = N'张%'

D.SELECT sname FROM student WHERE sname = N'%张%'

A.SELECT sno,sname FROM student WHERE sname LIKE N'张%'

B.SELECT sno,sname FROM student WHERE sname LIKE N'%张%'

C.SELECT sname FROM student WHERE sname = N'张%'

D.SELECT sname FROM student WHERE sname = N'%张%'