tag:blogger.com,1999:blog-5124641802818980374.post5205610253477286438..comments2023-09-06T11:58:30.752+02:00Comments on Oracle related stuff: Coalesce Subquery Transformation - COALESCE_SQUnknownnoreply@blogger.comBlogger2125tag:blogger.com,1999:blog-5124641802818980374.post-32532871415902573492012-03-26T22:08:56.993+02:002012-03-26T22:08:56.993+02:00Hi Mohamed,
thanks for the link. The paper is ver...Hi Mohamed,<br /><br />thanks for the link. The paper is very interesting and makes extensive use of the TPC-H sample queries, so I was obviously heading into the right direction with my comments.<br /><br />RandolfRandolfhttps://www.blogger.com/profile/13463198440639982695noreply@blogger.comtag:blogger.com,1999:blog-5124641802818980374.post-91203638798051988512012-03-26T17:04:48.880+02:002012-03-26T17:04:48.880+02:00Several months ago I read the following pdf docume...Several months ago I read the following pdf document<br />http://www.vldb.org/pvldb/2/vldb09-423.pdf<br />which seems dealing with the same subject.<br /><br />Their query rewrite is not exactly identical to the transformations done by CBO. Their basic rewrite is as follows<br /><br />select *<br /> from table_t t1<br />where<br /> ....<br />and exists (select 1<br /> from table_t t2<br /> where<br /> ...<br /> having sum(case when<br /> ...<br /> else 0 END) = 0);<br /><br />Best Regards<br /><br />Mohamed HouriMohamed Hourihttps://www.blogger.com/profile/11687776847553675567noreply@blogger.com