EJEMPLOS ROWNUM

first sort the rows and then extract five rows from that sorted dataset.

SQL> select *

2 from (

3 select question_id, created

4 from asktom.ate_submitted_questions

5 order by created desc

6 )

7 where rownum <= 5;

Listing 4: Disk size of total sales transactions

SQL> select num_rows, blocks*8192/1024/1024 mb

2 from user_tables

3 where table_name = 'SALES_TRANSACTIONS';

NUM_ROWS MB

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10308870 1522.625