单项选择题
A．SELECT S#,SNAME FROM S WHERE SNAME='李%' B．SELECT S#,SNAME FROM S WHERE SNAME LIKE '李%' C．SELECT S#,SNAME FROM S WHERE SNAME='%李％' D．SELECT S#,SNAME FROM S WHERE SNAME LIKE '％李％'
A．仅Ⅰ B．仅Ⅱ C．仅Ⅲ D．都不正确
A．并 B．选择 C．自然连接 D．θ连接