1、SELECT DISTINCT 列名称 FROM 表名称,为student表内容。
2、查询名叫李四的学生值显示一次,SELECT DISTINCT `name` FROM student。
3、根据age排序,SELECT DISTINCT `name` FROM student ORDER BY age。
4、根据name,age排序,从左至右优先顺序,SELECT DISTINCT `name` FROM student ORDER BY `name`,age。
5、按条件查询name为李四的学生。SELECT `name` FROM student WHERE `name`='李四'。
6、加上DISTINCT 去掉重复,SELECT DISTINCT `name` FROM student WHERE `name`='李四'。