首页查询优化

src/main/resources/mapper/course/CourseDetailsDao.xml

@@ -57,7 +57,7 @@
         <if test='null != dyShow and dyShow==2'>
             and (c.dy_show = #{dyShow} or c.dy_show is null)
         </if>
-        order by SUBSTR(uid, #{randomNum}, 6)
+        order by SUBSTR(uid, ${randomNum}, 6)
     </select>
 
 </mapper>