SQL语句：select * from student where sname like '张%' 实现了关系代数中的（）操作。
A: 选择
B: 投影
C: 并
D: 交
A: 选择
B: 投影
C: 并
D: 交
举一反三
- 【单选题】若要“检索名字为张某某的所有同学姓名”,SQL语句正确的是()。 A. SELECT Sname FROM Student WHERE Sname Like ‘张____’ B. SELECT Sname FROM Student WHERE Sname Like ‘张%’ C. SELECT Sname FROM Student WHERE Sname Like ‘张_’ D. SELECT Sname FROM Student WHERE Sname Not Like ‘张_ _’
- 从Student表检索姓周的学生，对应的SQL语句是( )。 A: Select * From Student Where Sname like '周%' B: Select * From Student Where Sname like '%周' C: Select * From Student Where Sname like '_周' D: Select * From Student Where Sname like '周_'
- 查询姓"张"的学生姓名,下列()语句不能实现。 A: SELECT sname FROM student WHERE left(sname,1)= '张' B: SELECT snameFROM student WHERE sname LIKE '张%' C: SELECT sname FROM student WHERE substring(sname,1,1)= '张' D: SELECT sname FROM student WHERE sname='张%'
- 根据用户在文本框txtName中输入的姓名对Student表进行查询，以下SQL语句定义正确的是__________________。 A: String sql=Select * from Student where Sname=+txtName.getText(); B: String sql=Select * from Student where Sname='+txtName.getText()+'; C: String sql=Select * from Student where Sname like +txtName.getText(); D: String sql=Select * from Student where Sname like '+txtName.getText()+';
- SQL语句：select distinct sdept from student 实现了关系代数中的（）操作。 A: 选择 B: 投影 C: 连接 D: 除