init data

server-db/src/main/java/cn/exploring/engine/server/db/dao/SpecialSqlMapper.java

@@ -203,6 +203,14 @@ public interface SpecialSqlMapper {
     )
     Map selectUnfinishLessonCount(@Param("userId") Integer userId);
 
+    /**
+     * 随机选择一个的学生
+     * @param classId
+     * @return
+     */
+    @Select("SELECT * FROM (SELECT * FROM student_info WHERE deleted = FALSE AND class_id = ${classId})  a1 LEFT JOIN ( SELECT (RAND()  * max(id) ) as nid  FROM  student_info WHERE deleted = FALSE AND class_id = ${classId}) a2 ON a1.id > a2.nid LIMIT 1")
+    Map<String, Object> selectRandomStudentInfo(@Param("classId") Integer classId);
+
     @Select("<script> " +
             "SELECT count(*) as count_info FROM user_reduce_info WHERE deleted = FALSE" +
             "<if test='lesson_average_point != null'>  AND lesson_average_point &gt;  ${lesson_average_point}  </if>" +