diff --git a/数据库/oracle/查询具体表占用的空间.md b/数据库/oracle/查询具体表占用的空间.md
new file mode 100644
index 0000000..1bb260c
--- /dev/null
+++ b/数据库/oracle/查询具体表占用的空间.md
@@ -0,0 +1,85 @@
+## 当前用户表占用空间
+```sql
+select SEGMENT_NAME as TABLE_NAME,BYTES/1024/1024 as 大小MB 
+from USER_SEGMENTS 
+where SEGMENT_TYPE='TABLE' 
+order by BYTES desc;
+```
+## 所有用户表占用空间
+```sql
+select OWNER,SEGMENT_NAME as TABLE_NAME,BYTES/1024/1024 as 大小MB
+from DBA_SEGMENTS
+where SEGMENT_TYPE='TABLE'
+order by OWNER,BYTES desc;
+```
+## 查询表空间及表空间所占空间大小
+```sql
+SELECT
+	tablespace_name,
+	sum( bytes ) / 1024 / 1024 
+FROM
+	dba_data_files 
+GROUP BY
+	tablespace_name;
+```
+## 查询表空间物理文件的名称及大小
+```sql
+SELECT
+	a.tablespace_name,
+	total,
+	free,
+	total - free AS used,
+	substr( free / total * 100, 1, 5 ) AS "FREE%",
+	substr( ( total - free ) / total * 100, 1, 5 ) AS "USED%" 
+FROM
+	(SELECT tablespace_name, sum( bytes ) / 1024 / 1024 AS total FROM dba_data_files GROUP BY tablespace_name) a,
+	(SELECT tablespace_name, sum( bytes ) / 1024 / 1024 AS free FROM dba_free_space GROUP BY tablespace_name) b 
+WHERE
+	a.tablespace_name = b.tablespace_name 
+ORDER BY
+	a.tablespace_name;
+```
+## 查询所有表空间以及每个表空间的大小，已用空间，剩余空间，使用率和空闲率
+```sql
+SELECT
+	a.tablespace_name,
+	total,
+	free,
+	total - free AS used,
+	substr( free / total * 100, 1, 5 ) AS "FREE%",
+	substr( ( total - free ) / total * 100, 1, 5 ) AS "USED%" 
+FROM
+	(SELECT tablespace_name, sum( bytes ) / 1024 / 1024 AS total FROM dba_data_files GROUP BY tablespace_name) a,
+	(SELECT tablespace_name, sum( bytes ) / 1024 / 1024 AS free FROM dba_free_space GROUP BY tablespace_name) b 
+WHERE
+	a.tablespace_name = b.tablespace_name 
+ORDER BY
+	a.tablespace_name;
+```
+## 查询某个具体的表所占空间的大小
+```sql
+SELECT
+	t.segment_name,
+	t.segment_type,
+	sum( t.bytes / 1024 / 1024 ) "占用空间(M)" 
+FROM
+	dba_segments t 
+WHERE
+	t.segment_type = 'TABLE' 
+	AND t.segment_name = 'TABLE_NAME' 
+GROUP BY
+	OWNER,
+	t.segment_name,
+	t.segment_type;
+```
+## 查看每个表所占空间大小
+```sql
+select * from (
+  select t.tablespace_name,t.owner, t.segment_name, t.segment_type, sum(t.bytes / 1024 / 1024) mb
+  from dba_segments t
+  where t.segment_type='TABLE'
+  group by t.tablespace_name,t.OWNER, t.segment_name, t.segment_type
+) t
+order by t.mb desc
+;
+```
\ No newline at end of file