Check Tablespace

SELECT   SUBSTR(SUB_QUERY.TABLESPACE_NAME,1,30) TABLESPACE,
         ROUND(SUM(SUB_QUERY.TOTAL1)/1024/1024,1) "TOTAL_MB",
         ROUND(SUM(SUB_QUERY.TOTAL1)/1024/1024,1)-ROUND(SUM(SUB_QUERY.SUM1)/1024/1024,1) "USED_MB",
         ROUND(SUM(SUB_QUERY.SUM1)/1024/1024,1) "FREE_MB",
         ROUND((ROUND(SUM(SUB_QUERY.TOTAL1)/1024/1024,1)-ROUND(SUM(SUB_QUERY.SUM1)/1024/1024,1))/ROUND(SUM(SUB_QUERY.TOTAL1)/1024/1024,1)*100,2) "USED_%"
FROM
         (SELECT   TABLESPACE_NAME,0 TOTAL1,SUM(BYTES) SUM1, MAX(BYTES) MAXB, COUNT(BYTES) CNT
          FROM     DBA_FREE_SPACE
          GROUP BY TABLESPACE_NAME
          UNION
          SELECT   TABLESPACE_NAME,SUM(BYTES) TOTAL1,0,0,0
          FROM     DBA_DATA_FILES
          GROUP BY TABLESPACE_NAME) SUB_QUERY
GROUP BY SUB_QUERY.TABLESPACE_NAME
ORDER BY TABLESPACE;