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Default orderBy research 2/17/2011

4 bytes removed, 12:14, 26 March 2011
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I checked the data and in xml file and the one I get when running the composed query in PostgreSQL. They are identical.<br/>
I ran the same tests in MySQL: I've got the same data as in PostgreSQL. The only difference is the order of rows, so I figured it has something to do with default ordering in PostgreSQL:<br/>
The null value sorts higher than any other value. In other words, with '''ascending''' sort order, '''null values''' <br/> sort at the '''end''', and with descending sort order, null values sort at the beginning.<br/> If not specified, '''<tt>ASC</tt>''' is assumed by '''default'''.<br/>
And in the MySQL:<br/>
When doing an ORDER BY, '''NULL values''' are presented '''first''' if you do ORDER BY ... ASC ('''default''') and last if you do ORDER BY ... DESC. <br/>
This explains why testUpdates gives the specified message, and I guess we have the same issue when we are trying to read '''without order by''' clause.
<br/>Solution: Every time we have ORDER BY we specify '''nulls first''' (this option is supported in PostgreSQL 8.3 and later).
Peter.liu
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