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Identify three situations in which you would NOT be able to drop a tablespace. (Choose three.)A.when the tablespace is onlineB.when the tablespace has 阅读全文
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Examine the commands executed in a DBA session:SQL> CREATE BIGFILE TABLESPACE MRKT2 DATAFILE '/u01/app/oracle/oradata/orcl/mrkt.dbf' size 10M LOGGING3 阅读全文
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You execute the following command to change the status of the SALES tablespace:SQL> ALTER TABLESPACE sales OFFLINE;Which statements describe the effec 阅读全文
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You execute a command to resize a data file, sales.dbf, of size 200 MB in your database:ALTER DATABASE DATAFILE '/remorse/sales.dbf' RESIZE 150M;Which 阅读全文
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--关联查询时爆了a.id无效然后测试了一下 --错误 select a.id, b.id, c.id from t1 a ,t2 b left join t3 c on c.id=a.id where a.id=b.id --正确 select a.id, b.id, c.id from t1 a left join t3 c on c.id=a.id , t2 b where a... 阅读全文
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a、row_number() over() row_number()over(partition by col1 order by col2)表示根据col1分组，在分组内部根据col2排序，而此函数计算的值就表示每组内部排序后的顺序编号（组内连续的唯一的）。 与rownum的区别在于：使用rown 阅读全文