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LINQ query on a DataTable
...w in myDataTable.AsEnumerable()
where myRow.Field<int>("RowNo") == 1
select myRow;
And as @Keith says, you'll need to add a reference to System.Data.DataSetExtensions
AsEnumerable() returns IEnumerable<DataRow>. If you need to convert IEnumerable<DataRow> to a DataTable, use the...
SQL Server: Difference between PARTITION BY and GROUP BY
...y're used in different places. group by modifies the entire query, like:
select customerId, count(*) as orderCount
from Orders
group by customerId
But partition by just works on a window function, like row_number:
select row_number() over (partition by customerId order by orderId)
as OrderN...
Finding duplicate values in MySQL
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Do a SELECT with a GROUP BY clause. Let's say name is the column you want to find duplicates in:
SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;
This will return a result with the name value in the first colum...
Why is 'this' a pointer and not a reference?
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@Omnifarious you could write &reinterpret_cast<char&>(this); to get the real address for overloading operator& (in fact, this is sort of what boost::addressof does).
– Johannes Schaub - litb
Jul 1 '10 at 22:57
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How dangerous is it to compare floating point values?
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[The 'right answer' glosses over selecting K. Selecting K ends up being just as ad-hoc as selecting VISIBLE_SHIFT but selecting K is less obvious because unlike VISIBLE_SHIFT it is not grounded on any display property. Thus pick your poison - select K or s...
How do I convert an interval into a number of hours with postgres?
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Probably the easiest way is:
SELECT EXTRACT(epoch FROM my_interval)/3600
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How to check for Is not Null And Is not Empty string in SQL server?
... ('A'),
(''),
(' '),
(NULL);
SELECT *
FROM T
WHERE C <> ''
Returns just the single row A. I.e. The rows with NULL or an empty string or a string consisting entirely of spaces are all excluded by this query.
SQL Fiddle
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How to remove a web site from google analytics
...e awhile to figure out.
Go to the Admin tab.
In the middle column, select the web property that you want to delete from the dropdown.
In the right-hand column, click on "View Settings." ("Property Settings" in dec. 2015)
At the bottom of the next page, select "Delete this view."
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Spring JPA selecting specific columns
...Spring JPA to perform all database operations. However I don't know how to select specific columns from a table in Spring JPA?
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How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?
...(1) (in relation to the upper bound). Maybe the longest english word is 50 characters?
8 Answers
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