diff --git a/src/main/java/org/triumers/kmsback/post/command/Application/service/CmdPostServiceImpl.java b/src/main/java/org/triumers/kmsback/post/command/Application/service/CmdPostServiceImpl.java
index 4e05a363..70cec4bf 100644
--- a/src/main/java/org/triumers/kmsback/post/command/Application/service/CmdPostServiceImpl.java
+++ b/src/main/java/org/triumers/kmsback/post/command/Application/service/CmdPostServiceImpl.java
@@ -87,13 +87,26 @@ public CmdPostAndTagsDTO registPost(CmdPostAndTagsDTO post) throws NotLoginExcep
 
     public static String sanitizeHTML(String html) {
 
+        // 공백, 줄바꿈 대체
+        String spacePlaceholder = "___SPACE___";
+        String newlinePlaceholder = "___NEWLINE___";
+        String htmlWithPlaceholders = html
+                .replaceAll(" ", spacePlaceholder)
+                .replaceAll("\n", newlinePlaceholder)
+                .replaceAll("\r\n", newlinePlaceholder);
+
         Whitelist whitelist = Whitelist.relaxed();
         // 허용되지 않을 태그와 속성 추가
         whitelist.removeTags("script", "style", "head", "header", "foot", "footer");
-        whitelist.removeAttributes( "style","onclick");
+        whitelist.removeAttributes("style", "onclick");
+
+        String cleanedHtmlWithPlaceholders = Jsoup.clean(htmlWithPlaceholders, whitelist);
+
+        String cleanedHtml = cleanedHtmlWithPlaceholders
+                .replaceAll(spacePlaceholder, " ")
+                .replaceAll(newlinePlaceholder, "\n");
 
-        String cleanedHTML = Jsoup.clean(html, whitelist);
-        return cleanedHTML;
+        return cleanedHtml;
     }
 
     public List<CmdTag> registTag(List<CmdTagDTO> tags, int postId) {
diff --git a/src/main/java/org/triumers/kmsback/tab/command/Application/service/CmdTabServiceImpl.java b/src/main/java/org/triumers/kmsback/tab/command/Application/service/CmdTabServiceImpl.java
index 159eedde..80d505f1 100644
--- a/src/main/java/org/triumers/kmsback/tab/command/Application/service/CmdTabServiceImpl.java
+++ b/src/main/java/org/triumers/kmsback/tab/command/Application/service/CmdTabServiceImpl.java
@@ -35,9 +35,15 @@ public CmdTabServiceImpl(CmdJoinEmployeeRepository cmdJoinEmployeeRepository, Cm
     @Override
     @Transactional
     public CmdJoinEmployeeDTO addEmployeeTab(CmdJoinEmployeeDTO employee) {
-        CmdJoinEmployee newEmployee = new CmdJoinEmployee(employee.getIsLeader(),employee.getEmployeeId(),
-                                                          employee.getTabId());
-        cmdJoinEmployeeRepository.save(newEmployee);
+
+        CmdJoinEmployee newEmployee = cmdJoinEmployeeRepository.
+                findByEmployeeIdAndTabId(employee.getEmployeeId(), employee.getTabId());
+
+        if(newEmployee == null){
+            newEmployee = new CmdJoinEmployee(employee.getIsLeader(),employee.getEmployeeId(),
+                    employee.getTabId());
+            cmdJoinEmployeeRepository.save(newEmployee);
+        }
 
         CmdJoinEmployeeDTO joinEmployeeDTO = new CmdJoinEmployeeDTO(newEmployee.getId(), newEmployee.getIsLeader(), newEmployee.getEmployeeId(), newEmployee.getTabId());
         return joinEmployeeDTO;
@@ -52,7 +58,8 @@ public CmdJoinEmployeeDTO deleteEmployeeTab(CmdJoinEmployeeDTO employee) {
 
         cmdJoinEmployeeRepository.deleteById(deleteEmployee.getId());
 
-        CmdJoinEmployeeDTO deleteEmployeeDTO = new CmdJoinEmployeeDTO(deleteEmployee.getId(), deleteEmployee.getIsLeader(), deleteEmployee.getEmployeeId(), deleteEmployee.getTabId());
+        CmdJoinEmployeeDTO deleteEmployeeDTO = new CmdJoinEmployeeDTO(deleteEmployee.getId(), deleteEmployee.getIsLeader(),
+                                                                      deleteEmployee.getEmployeeId(), deleteEmployee.getTabId());
         return deleteEmployeeDTO;
     }
 
@@ -63,12 +70,16 @@ public CmdTabRelationDTO registTab(CmdTabRelationDTO tabRelation, int employeeId
         CmdTabDTO topTab = registTopTab(tabRelation.getTopTab());
         CmdTabDTO bottomTab = registBottomTab(tabRelation.getBottomTab());
 
-        CmdTabRelation newTab = new CmdTabRelation(tabRelation.getIsPublic(), bottomTab.getId(),
-                topTab.getId(), tabRelation.getTeamId());
-        cmdTabRelationRepository.save(newTab);
+        CmdTabRelation newTab = cmdTabRelationRepository.findByBottomTabIdAndTopTabIdAndTeamId(bottomTab.getId(), topTab.getId(), tabRelation.getTeamId());
 
-        CmdJoinEmployeeDTO joinEmployee = new CmdJoinEmployeeDTO(true, employeeId, newTab.getId());
-        addEmployeeTab(joinEmployee);
+        if(newTab == null){
+            newTab = new CmdTabRelation(tabRelation.getIsPublic(), bottomTab.getId(),
+                    topTab.getId(), tabRelation.getTeamId());
+            cmdTabRelationRepository.save(newTab);
+
+            CmdJoinEmployeeDTO joinEmployee = new CmdJoinEmployeeDTO(true, employeeId, newTab.getId());
+            addEmployeeTab(joinEmployee);
+        }
 
         CmdTabRelationDTO newTabRelation = new CmdTabRelationDTO(newTab.getId(), newTab.getIsPublic(),
                 bottomTab, topTab, newTab.getTeamId());
diff --git a/src/main/java/org/triumers/kmsback/tab/command/domain/repository/CmdTabRelationRepository.java b/src/main/java/org/triumers/kmsback/tab/command/domain/repository/CmdTabRelationRepository.java
index ab4a4e2b..58d8894e 100644
--- a/src/main/java/org/triumers/kmsback/tab/command/domain/repository/CmdTabRelationRepository.java
+++ b/src/main/java/org/triumers/kmsback/tab/command/domain/repository/CmdTabRelationRepository.java
@@ -9,4 +9,6 @@
 public interface CmdTabRelationRepository extends JpaRepository<CmdTabRelation, Integer> {
 
     CmdTabRelation findById(int id);
+
+    CmdTabRelation findByBottomTabIdAndTopTabIdAndTeamId(Integer bottomId, Integer topId, Integer teamId);
 }
diff --git a/src/main/resources/org/triumers/kmsback/group/query/repository/GroupMapper.xml b/src/main/resources/org/triumers/kmsback/group/query/repository/GroupMapper.xml
index 91ede638..282d888c 100644
--- a/src/main/resources/org/triumers/kmsback/group/query/repository/GroupMapper.xml
+++ b/src/main/resources/org/triumers/kmsback/group/query/repository/GroupMapper.xml
@@ -48,6 +48,8 @@
           JOIN tbl_department AS dept ON team.DEPARTMENT_ID = dept.ID
           JOIN tbl_center AS center ON dept.CENTER_ID = center.ID
          WHERE emp.ID = #{employeeId}
+            OR (tabRel.TEAM_ID = (SELECT E.TEAM_ID FROM tbl_employee E WHERE E.ID = #{employeeId})
+                                                                               AND tabRel.TOP_TAB_ID = 2);
     </select>
 
     <select id="findGroupIdByEmployeeId" parameterType="int">