diff --git a/src/main/java/com/lovenav/dao/CommentDao.java b/src/main/java/com/lovenav/dao/CommentDao.java
index e779469..fbd4a7c 100644
--- a/src/main/java/com/lovenav/dao/CommentDao.java
+++ b/src/main/java/com/lovenav/dao/CommentDao.java
@@ -43,4 +43,6 @@ public interface CommentDao {
      */
 
     List<CommentNode> querySecondCommentList(Integer UrlId);
+
+    public String queryChildId(String commentId);
 }
\ No newline at end of file
diff --git a/src/main/java/com/lovenav/service/CommentService.java b/src/main/java/com/lovenav/service/CommentService.java
index 478f791..b88521b 100644
--- a/src/main/java/com/lovenav/service/CommentService.java
+++ b/src/main/java/com/lovenav/service/CommentService.java
@@ -26,4 +26,6 @@ public interface CommentService {
     List<CommentNode> queryCommentByUrlId (Integer UrlId );
 
     CommentUser queryCommentUserById(Integer id);
+
+    public String SelectChildAndDelete(String commentId);
 }
diff --git a/src/main/java/com/lovenav/service/serviceImpl/CommentServiceImpl.java b/src/main/java/com/lovenav/service/serviceImpl/CommentServiceImpl.java
index ec52ab0..3ab13fb 100644
--- a/src/main/java/com/lovenav/service/serviceImpl/CommentServiceImpl.java
+++ b/src/main/java/com/lovenav/service/serviceImpl/CommentServiceImpl.java
@@ -10,6 +10,7 @@ import com.lovenav.entity.CommentUser;
 import com.lovenav.entity.User;
 import com.lovenav.service.CommentService;
 import io.swagger.models.auth.In;
+import org.checkerframework.checker.units.qual.C;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import java.util.HashMap;
@@ -169,5 +170,21 @@ public class CommentServiceImpl implements CommentService {
         }
         return firstList;
     }
+    public String SelectChildAndDelete(String commentId)
+    {
+
+        String child = commentDao.queryChildId(commentId);
+        String [] childrens = child.split(",");
+        int flag = 0;
+        for(String id : childrens)
+        {
+            flag = commentDao.deleteByPrimaryKey(Integer.valueOf(id));
+            if (String.valueOf(flag).equals("0")){
+                return "出现错误";
+            }
+        }
+        return "处理完成";
+    }
+
 
 }
diff --git a/src/main/resources/mybatis/CommentDao.xml b/src/main/resources/mybatis/CommentDao.xml
index 7e9a7cc..d59e415 100644
--- a/src/main/resources/mybatis/CommentDao.xml
+++ b/src/main/resources/mybatis/CommentDao.xml
@@ -55,6 +55,19 @@
     delete from ln_comment
     where id = #{id,jdbcType=INTEGER}
   </delete>
+
+  <select id="queryChildId" parameterType="java.lang.String" resultType="java.lang.String">
+    SELECT t3.ischild
+    FROM(SELECT t1.*,
+                IF (FIND_IN_SET(root_comment_id, @pids) > 0,@pids := CONCAT(@pids, ',', id),'0') AS ischild
+         FROM(SELECT t.id,t.root_comment_id
+              FROM ln_comment AS t
+              ORDER BY t.id ASC) t1,
+             (SELECT @pids := #{commentId,jdbcType=INTEGER}) t2) t3
+    WHERE ischild != '0'
+  </select>
+
+
   <insert id="insert" keyColumn="id" keyProperty="id" parameterType="com.lovenav.entity.Comment" useGeneratedKeys="true">
     insert into ln_comment (url_id, user_id, content, 
       root_comment_id, like_count, comment_time,