oracle表空间使用率查询语句
Oracle数据库中的表空间是用于存储数据的逻辑结构，它由一个或多个数据文件组成。表空间使用率是指表空间中已使用的空间与总空间的比值，可以通过查询语句来获取。下面列举了十个查询表空间使用率的语句。
1. 查询所有表空间的使用率
```
SELECT tablespace_name, ROUND((used_space / total_space) * 100, 2) AS usage_percentage
FROM (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS used_space
    FROM dba_segments
    GROUP BY tablespace_name
) t1
JOIN (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS total_space
    FROM dba_data_files
    GROUP BY tablespace_name
) t2 ON t1.tablespace_name = t2.tablespace_name;
```
2. 查询指定表空间的使用率
```
SELECT tablespace_name, ROUND((used_space / total_space) * 100, 2) AS usage_percentage
FROM (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS used_space
    FROM dba_segments
    WHERE tablespace_name = 'TABLESPACE_NAME'
    GROUP BY tablespace_name
) t1
JOIN (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS total_space
    FROM dba_data_files
    WHERE tablespace_name = 'TABLESPACE_NAME'
    GROUP BY tablespace_name
) t2 ON t1.tablespace_name = t2.tablespace_name;
```
3. 查询所有表空间的使用情况及排序
```
SELECT tablespace_name, ROUND((used_space / total_space) * 100, 2) AS usage_percentage
FROM (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS used_space
    FROM dba_segments
    GROUP BY tablespace_name
) t1
JOIN (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS total_space
    FROM dba_data_files
    GROUP BY tablespace_name
) t2 ON t1.tablespace_name = t2.tablespace_name
ORDER BY usage_percentage DESC;
```
4. 查询指定表空间的使用情况及排序
```
SELECT tablespace_name, ROUND((used_space / total_space) * 100, 2) AS usage_percentage
空间音乐查询
FROM (
    SELECT tablespace_name, SUM(bytes) / 1024 / 1024 AS used_space
    FROM dba_segments
    WHERE tablespace_name = 'TABLESPACE_NAME'