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MySQL - force not to use cache for testing speed of query
...ACHE (MySQL 5.7) option in your query.
(MySQL 5.6 users click HERE )
eg.
SELECT SQL_NO_CACHE * FROM TABLE
This will stop MySQL caching the results, however be aware that other OS and disk caches may also impact performance. These are harder to get around.
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How do I delete a fixed number of rows with sorting in PostgreSQL?
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You could try using the ctid:
DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly,...
How can I copy the output of a command directly into my clipboard?
...mewhere else other than a X application, try this one:
cat file | xclip -selection clipboard
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Convert Linq Query Result to Dictionary
... @pawan - that doesn't look right. I'd expect var servers = list.Select( s => new { s.ProjectName, Url = "tcp://" + s.BuildMachineName + ":" + s.PortNumber + "/CruiseManager.rem" } ).ToDictionary( s => s.ProjectName, s.Url ); This creates a dictionary keyed by project name of projec...
efficient way to implement paging
...inq (with SQL 2005 / 2008 as database server) your query will be using the Select ROW_NUMBER() Over ... statement, with is somehow direct paging in the SQL engine.
Giving you an example, I have a db table called mtcity and I wrote the following query (work as well with linq to entities):
using (Da...
SQL query to get all values a enum can have
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If you want an array:
SELECT enum_range(NULL::myenum)
If you want a separate record for each item in the enum:
SELECT unnest(enum_range(NULL::myenum))
Additional Information
This solution works as expected even if your enum is not in the...
Getting all selected checkboxes in an array
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function get_selected_checkboxes_array(){ var ch_list=Array(); $("input:checkbox[type=checkbox]:checked").each(function(){ch_list.push($(this).val());}); ...
“CASE” statement within “WHERE” clause in SQL Server 2008
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Try the following:
select * From emp_master
where emp_last_name=
case emp_first_name
when 'test' then 'test'
when 'Mr name' then 'name'
end
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Maven error “Failure to transfer…”
...ed.properties).
Then go back into Eclipse, Right-click on the project and select Maven > Update Project. I selected to "Force Update of Snapshots/Releases". Click Ok and the dependencies finally resolved correctly.
shar...
How do I query for all dates greater than a certain date in SQL Server?
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select *
from dbo.March2010 A
where A.Date >= Convert(datetime, '2010-04-01' )
In your query, 2010-4-01 is treated as a mathematical expression, so in essence it read
select *
from dbo.March2010 A
where A.Date &g...