Join test and control groups and compute metric differences

SQL_join.sql

SELECT     A.DEVICE_ID_TEST,A.DEVICE_OS_TEST, A.USAGE_TEST, B.DEVICE_ID_CTRL, B.DEVICE_OS_CTRL, B.USAGE_CTRL,
            (A.CURR_RETAIL_PRC_TEST)-(B.CURR_RETAIL_PRC_CTRL) AS RETAIL_PRICE,
            (A.DEVICE_RAM_TEST)-(B.DEVICE_RAM_CTRL) AS RAM,
           (A.AGE_TEST)-(B.AGE_CONTROL) AS AGE,
           (A.DEVICE_STORAGE_TEST)-(B.DEVICE_STORAGE_CTRL) AS STORAGE,
          (A.SCREEN_INCH_TEST)-(B.SCREEN_INCH_CTRL) AS SCREEN_SIZE
 FROM   
( 
     SELECT DEVICE_ID AS DEVICE_ID_TEST
          , DEVICE_DESC AS DEVICE_DESC_TEST
          , CURR_RETAIL_PRC AS CURR_RETAIL_PRC_TEST
          , DEVICE_RAM AS DEVICE_RAM_TEST
          , AGE AS AGE_TEST
          , DEVICE_STORAGE AS DEVICE_STORAGE_TEST
          , SCREEN_INCH AS SCREEN_INCH_TEST
          , DEVICE_OS AS DEVICE_OS_TEST
          , USAGE AS USAGE_TEST
    FROM TABLE_NAME
    WHERE BRAND_FLAG = 1
  )A
INNER JOIN 
  (
    SELECT DEVICE_ID AS DEVICE_ID_CTRL
          , DEVICE_DESC AS DEVICE_DESC_CTRL
          , CURR_RETAIL_PRC AS CURR_RETAIL_PRC_CTRL
          , DEVICE_RAM AS DEVICE_RAM_CTRL
          , AGE AS AGE_TEST
          , DEVICE_STORAGE AS DEVICE_STORAGE_CTRL
          , SCREEN_INCH AS SCREEN_INCH_CTRL
          , DEVICE_OS AS DEVICE_OS_CTRL
          , USAGE AS USAGE_CTRL
    FROM TABLE_NAME
    WHERE BRAND_FLAG = 0
  )B
 ON A.DEVICE_OS_TEST = B.DEVICE_OS_CTRL AND A.USAGE_TEST = B.USAGE_CTRL
 )