The fastest paging speed in Oracle --- SQL statement explanation

RowidSQL statement interpretation select * frommytable2s1whererowidin (selectridfrom (selectrownumr1, ridfrom (selectrowidrid

Rowid SQL statement interpretation select * from mytable2 s1 where rowid in (select rid from (select rownum r1, rid from (select rowid rid

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The fastest paging speed in Oracle --- SQL statement explanation

[Date: 2011-12-19] Source: Linux Author: n52376531 [Font:]

Rowid SQL statement explanation

Select * from mytable2 s1 where rowid in (select rid from (select rownum r1, rid from (select rowid rid from mytable2) where rownum <= 10) where r1> = 3 );

Select rowid rid from mytable2 indicates using rowid to identify mytable2 (rowid is an Oracle System Function)

Select rownum r1, rid from (select rowid rid from mytable2) where rownum <= 10 indicates adding the rownum field (rownum is an oracle system function). The table found in the previous step is used as an embedded table.

Rownum <= 10 indicates the first 10 records to be queried.

Select rid from (select rownum r1, rid from (select rowid rid from mytable2) where rownum <= 10) where r1> = 1) rownum> = 3 returns the rowid Value

Rownum> = 3 indicates that the first 10 records not including the first 3 Records

Where rowid in indicates that the rowid result queried in the subquery matches the rowid in mytable2.

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