update 简化查询用户功能

ruoyi-system/src/main/resources/mapper/system/SysUserRoleMapper.xml

@@ -8,5 +8,10 @@
         <result property="userId" column="user_id"/>
         <result property="roleId" column="role_id"/>
     </resultMap>
+    <select id="selectUserIdByRoleId" resultType="Long">
+        select u.user_id from sys_user u
+        inner join sys_user_role ur
+            on u.user_id = ur.user_id and ur.role_id = #{roleId}
+    </select>
 
 </mapper>