I'm running a query and its taking a age to execute, looking at the execution plan I can see that 51% of the cost is in the SORT? when in the actual query i am not ORDERING BY anything. Anyone got ...
I have not been able to find a clear indication of the impact table indexes have on the algorithmic order of table operations. I am not interested in the nuts & bolts of specific implementations; ...
I'm using PostgreSQL 8.4, but would like a standard SQL solution if possible. Consider the following table. corrmodel=# SELECT * from data limit 1; id | datasubgroup_id | datafile_id | ...
I am trying to get rid of a filesort operation (and preferably also optimize a bottleneck query). We are using an innodb mysql table as a queue to process various incoming business activities. It is ...
How can I sort in Oracle a Varchar2 or NVarchar2 column to be in my own custom defined order. Or are any existing options available that will put letters first, then numbers, then all special ...
Why is it that when we have a NULL value in a column and we order by the value ascending, the NULLs are sorted first? select 1 as test union all select 2 union all select NULL union all select 3 ...