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10 things in SQL Server (which don’t work as expected) 20 Jul 2013 | 12:00 am
10. Unique NULL When declaring UNIQUE constraints on columns, SQL Server treats all NULL values as unique. This means you can’t have more than one NULL value in a unique column. This behavior violat...
Score charts, friendship lists and unique multiple columns: easy with SQL Server’s indexed views 28 Jun 2013 | 12:00 am
SQL Server supports a really useful feature called indexed views. This means it lets you materialize results of some queries and build indexes over them. It’s as if you haven’t actually run the query ...
SQL Server: joining NULL values 9 May 2013 | 12:00 am
A way to emulate IS DISTINCT FROM on SQL Server to join on NULL values
INSERT … SELECT … OUTPUT …: returning source table data 25 Mar 2013 | 11:00 pm
A way to output source table colums with INSERT ... SELECT in SQL Server.
Empty row if condition does not match 4 Jan 2013 | 12:00 am
How to make a query always return a NULL row on a non-match
Happy New Year! 1 Jan 2013 | 12:00 am
A satellite view of Earth in PostgreSQL
Happy New Year! 1 Jan 2012 | 09:00 am
This winter is anomalously warm in Europe, there is no snow and no New Year mood. So today we will be drawing a snowflake in PostgreSQL. #1. A little theory Core of a snowflake is six large symmetri...
What’s UNPIVOT good for? 1 Jul 2011 | 07:00 am
Answering questions asked on the site. Karen asks: … I’ve always thought PIVOT and UNPIVOT are signs of a poorly designed database. I mean, is there a legitimate use for them if your model is OK? I...
Shared Plan and Algorithm Network Cache (SPANC) 2 Apr 2011 | 07:00 am
Due to the nature of my work I have to deal with various database systems. While SQL is more or less standardized, the optimizers are implemented differently in the different systems. Some systems ca...
MySQL: GROUP BY in UNION 31 Mar 2011 | 07:00 am
From Stack Overflow: I have a query where I have a custom developed UDF that is used to calculate whether or not certain points are within a polygon (first query in UNION) or circular (second query i...
