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IN vs OR in the SQL WHERE Clause
...h are nearly instant. When the column is not indexed I got these results:
SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000);
1 row fetched in 0.0032 (1.2679 seconds)
SELECT COUNT(*) FROM t_inner WHERE val = 1000 OR val = 2000 OR val = 3000 OR val = 40...
中文网（自研/维护）拓展 · App Inventor 2 中文网
...riginal call and the row ID of the new or updated row are provided.
AfterSelect(tag,rowCount,rows)
This event fires after an asynchronous Select call. The tag specified in the original call, the number of returned rows, and the result rows are provided.
AfterUpdate(tag,rowCount)
This event f...
How do I repeat an edit on multiple lines in Vim?
...al block by using
" allow the . to execute once for each line of a visual selection
vnoremap . :normal .<CR>
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When should I use a composite index?
...nefit a query that uses those fields for joining, filtering, and sometimes selecting. It will also benefit queries that use left-most subsets of columns in that composite. So the above index will also satisfy queries that need
index( column_A, column_B, column_C )
index( column_A, column_B )
index(...
How can I make Jenkins CI with Git trigger on pushes to master?
...The wiki says "when creating a job, specify URL under "Github project" and select Git specify URL under "Source Code Management". It says "This trigger only kicks Git plugin internal polling algo for every incoming event against matched repo." I think that means it pretty much does the Poll SCM like...
How can I easily convert DataReader to List? [duplicate]
... writing an extension method for this:
public static IEnumerable<T> Select<T>(this IDataReader reader,
Func<IDataReader, T> projection)
{
while (reader.Read())
{
yield return projection(reader);
}
}
You can then use LINQ...
Could not instantiate class named MKMapView
... project to bring the project settings. Under Targets, click your project, select from the upper toolbar "Build Phases". Under "Link binary With Libraries" tab, you will see the list of frameworks included in your project. Click the "+" button and add MapKit library from the shown list to your proje...
Import CSV file into SQL Server
...e using SQL Server Management Studio
• Right click on your database and select Tasks -> Import Data...
• Click the Next > button
• For the Data Source, select Flat File Source. Then use the Browse button to select the CSV file. Spend some time configuring how you want the data to be...
How to modify a pull request on GitHub to change target branch to merge into?
...e new pull request in their dashboard the next time they sign in.
If you select as a base branch the one that the original maintainer (the owner) wants, your PR should merge from your branch (unchanged) to the new base branch.
...
How to create a sequence of integers in C#?
...
Linq projection with the rarely used indexer overload (i):
(new int[11]).Select((o,i) => i)
I prefer this method for its flexibilty.
For example, if I want evens:
(new int[11]).Select((item,i) => i*2)
Or if I want 5 minute increments of an hour:
(new int[12]).Select((item,i) => i*5...