大约有 43,000 项符合查询结果（耗时：0.0392秒） [XML]
How to get the top 10 values in postgresql?
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For this you can use limit
select *
from scores
order by score desc
limit 10
If performance is important (when is it not ;-) look for an index on score.
Starting with version 8.4, you can also use the standard (SQL:2008) fetch first
select *
from...
Max or Default?
...d, you can get around this limitation by casting to a nullable within your select. My VB is a little rusty, but I think it'd go something like this:
Dim x = (From y In context.MyTable _
Where y.MyField = value _
Select CType(y.MyCounter, Integer?)).Max
Or in C#:
var x = (from y...
SQL Server: Get table primary key using sql query [duplicate]
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I also found another one for SQL Server:
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE OBJECTPROPERTY(OBJECT_ID(CONSTRAINT_SCHEMA + '.' + QUOTENAME(CONSTRAINT_NAME)), 'IsPrimaryKey') = 1
AND TABLE_NAME = 'TableName' AND TABLE_SCHEMA = 'Schema'
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How do you get the index of the current iteration of a foreach loop?
...things in parallel ... that's exactly what the indexing form of Enumerable.Select does.
– Jim Balter
Oct 26 '13 at 0:57
11
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How to fix Error: “Could not find schema information for the attribute/element” by creating schema
...tudio, open your app.config or web.config file.
Go to the "XML" menu and select "Create Schema". This action should create a new file called "app.xsd" or "web.xsd".
Save that file to your disk.
Go back to your app.config or web.config and in the edit window, right click and select properties. From...
Is there a CSS parent selector?
How do I select the <li> element that is a direct parent of the anchor element?
33 Answers
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jQuery - Detecting if a file has been selected in the file input [duplicate]
...lt;/script>
You may want to add IDs to your input and span so you can select based on those to be specific to the elements you are concerned with and not other file inputs or spans in the DOM.
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How to set IntelliJ IDEA Project SDK
... for me to set up the Project SDK. When I click on "JDK" it asks for me to select the home directory of the JDK as shown in this image.
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What is a C++ delegate?
...lic:
virtual void Fn( int i )
{
}
};
int main( int /*argc*/, char * /*argv*/ )
{
A a;
CCallback<A> cbk( a, &A::Fn );
cbk.Execute( 3 );
}
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improve this ans...
“Large data” work flows using pandas
...ns?
What will typical operations look like. E.g. do a query on columns to select a bunch of rows and specific columns, then do an operation (in-memory), create new columns, save these.
(Giving a toy example could enable us to offer more specific recommendations.)
After that processing, then what do...