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This article mainly introduces the example analysis of Oracle paging query, the article is very detailed, has a certain reference value, interested friends must read it!

Detailed explanation of Oracle paging query examples

1.Oracle paging query:

SELECT * FROM (SELECT A.S., ROWNUM RN FROM (SELECT * FROM tab) A WHERE ROWNUM = 21

This page takes less time and is more efficient than the one below.

two。

Select * from (select c. Mag Rownum rn from tab c) where rn between 21 and 40

Comparing the two writing methods, in most cases, the first query is much more efficient than the second. This is because in CBO optimization mode, Oracle can push the outer query conditions to the inner query to improve the execution efficiency of the inner query. For the first query statement, the query condition WHERE ROWNUM of the second layer

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