大约有 42,000 项符合查询结果（耗时：0.0246秒） [XML]
Linq: GroupBy, Sum and Count
...a" is coming from, but the problem in the console app is that you're using SelectMany to look at each item in each group.
I think you just want:
List<ResultLine> result = Lines
.GroupBy(l => l.ProductCode)
.Select(cl => new ResultLine
{
ProductName =...
Removing duplicate rows from table in Oracle
...
Use the rowid pseudocolumn.
DELETE FROM your_table
WHERE rowid not in
(SELECT MIN(rowid)
FROM your_table
GROUP BY column1, column2, column3);
Where column1, column2, and column3 make up the identifying key for each record. You might list all your columns.
...
UPDATE multiple tables in MySQL using LEFT JOIN
...= t1.id
SET t1.col1 = newvalue
WHERE t2.id IS NULL
Note that for a SELECT it would be more efficient to use NOT IN / NOT EXISTS syntax:
SELECT t1.*
FROM t1
WHERE t1.id NOT IN
(
SELECT id
FROM t2
)
See the article in my blog for performance details...
IntelliJ: Working on multiple projects
...ven Projects" window (View > Tool Windows > Maven Projects) and then select the additional pom file you want to import.
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How do I select child elements of any depth using XPath?
...
If you are using the XmlDocument and XmlNode.
Say:
XmlNode f = root.SelectSingleNode("//form[@id='myform']");
Use:
XmlNode s = f.SelectSingleNode(".//input[@type='submit']");
It depends on the tool that you use. But .// will select any child, any depth from a reference node.
...
visual c++: #include files from other projects in the same solution
...n.
To access the project configuration:
Right-click on the project, and select Properties.
Select Configuration Properties->C/C++->General.
Set the path under Additional Include Directories.
How to include
To include the header file, simply write the following in your code:
#include "fi...
SQL Server: Query fast, but slow from procedure
...:
CREATE PROCEDURE GetOrderForCustomers(@CustID varchar(20))
AS
BEGIN
SELECT *
FROM orders
WHERE customerid = @CustID
END
Fast way:
CREATE PROCEDURE GetOrderForCustomersWithoutPS(@CustID varchar(20))
AS
BEGIN
DECLARE @LocCustID varchar(20)
SET @LocCustID = @CustID
SELEC...
ERROR: permission denied for sequence cities_id_seq using Postgres
...
Since PostgreSQL 8.2 you have to use:
GRANT USAGE, SELECT ON SEQUENCE cities_id_seq TO www;
GRANT USAGE - For sequences, this privilege allows the use of the currval and nextval functions.
Also as pointed out by @epic_fil in the comments you can grant permissions to all th...
SQLite: How do I save the result of a query as a CSV file?
... file output.
sqlite> .mode csv
sqlite> .output test.csv
sqlite> select * from tbl1;
sqlite> .output stdout
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How to link a Facebook app with an existing fan page
...roducts").
Change your page name to mach your App name.
Go to your App and select "App Details"
Under "Contact Info" you will find "App Page". There you will be able to create a new page or if all went well, select your page from a list.
I found the info in the little question-mark next to "App pa...