部门列表api返回部门的学员数量

src/main/resources/mapper/DepartmentMapper.xml

@@ -15,8 +15,13 @@
     </resultMap>
 
     <sql id="Base_Column_List">
-        id,name,parent_id,
-        parent_chain,sort,created_at,
+        id,name,parent_id,
+        parent_chain,sort,created_at,
         updated_at
     </sql>
+    <select id="getDepartmentsUserCount" resultType="xyz.playedu.api.types.mapper.DepartmentsUserCountMapRes">
+        SELECT `dep_id`, count(1) AS `total`
+        FROM user_department
+        GROUP BY dep_id;
+    </select>
 </mapper>