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Favourite performance tuning tricks [closed]
...n-optimal query plan
Break up the Join
Can you break up the join?
Pre-select foreign keys into a temporary table
Do half the join and put results in a temporary table
Are you using the right kind of temporary table?
#temp tables may perform much better than @table variables with large volum...
The cast to value type 'Int32' failed because the materialized value is null
...
where u.ID == userID
select (int?)ch.Amount).Sum() ?? 0;
This first casts to int? to tell the C# compiler that this expression can indeed return null, even though Sum() returns an int. Then we use the normal ?? operator to handle the null case....
Func vs. Action vs. Predicate [duplicate]
...s probably most commonly used in LINQ - for example in projections:
list.Select(x => x.SomeProperty)
or filtering:
list.Where(x => x.SomeValue == someOtherValue)
or key selection:
list.Join(otherList, x => x.FirstKey, y => y.SecondKey, ...)
Action is more commonly used for th...
Inspect hovered element in Chrome?
...er over the element to bring up the tooltip, right click as if you were to select 'Inspect Element'. Leaving that context menu open, move the focus over to the dev tools. The html for the tooltip should show up next to the element its a tooltip for in the HTML. Then you can look at it as if it were ...
What are the differences between 'call-template' and 'apply-templates' in XSL?
...ower of XSLT: It takes any number of XML nodes (whatever you define in the select attribute), iterates them (this is important: apply-templates works like a loop!) and finds matching templates for them:
<!-- sample XML snippet -->
<xml>
<foo /><bar /><baz />
</xml...
Reject binary with state waiting for review (can't find reject binary button)
...
In iTunes connect, from 'My apps', select
Click your application, then
Make sure you are on the 'Versions' tab, and that the correct version is selected.
Click 'Remove this version from review' located in the info bubble.
See below
...
Difference between JOIN and INNER JOIN
...nal,
or you can specify CROSS JOIN.
OR
For an inner join, the syntax is:
SELECT ...
FROM TableA
[INNER] JOIN TableB
(in other words, the "INNER" keyword is optional - results are the same
with or without it)
share
...
PostgreSQL wildcard LIKE for any of a list of words
... can use Postgres' SIMILAR TO operator which supports alternations, i.e.
select * from table where lower(value) similar to '%(foo|bar|baz)%';
share
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How to build a query string for a URL in C#?
...om key in nvc.AllKeys
from value in nvc.GetValues(key)
select string.Format(
"{0}={1}",
HttpUtility.UrlEncode(key),
HttpUtility.UrlEncode(value))
).ToArray();
return "?" + string.Join("&", array);
}
I imagine there...
mysql error 1364 Field doesn't have a default values
...nt tool, such as phpMyAdmin: -- verified that the mode was previously set select @@GLOBAL.sql_mode; -- UPDATE MODE SET @@global.sql_mode= 'YOUR_VALUE';
– anasanjaria
Dec 4 '13 at 18:17
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