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What columns generally make good indexes?
...earching the results speedily from tables. So it is most important step to select which columns to be indexed. There are two major places where we can consider indexing: columns referenced in the WHERE clause and columns used in JOIN clauses. In short, such columns should be indexed against which yo...
Freezing Row 1 and Column A at the same time
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Select cell B2 and click "Freeze Panes" this will freeze Row 1 and Column A.
For future reference, selecting Freeze Panes in Excel will freeze the rows above your selected cell and the columns to the left of your selected ce...
Difference between SelectedItem, SelectedValue and SelectedValuePath
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Their names can be a bit confusing :). Here's a summary:
The SelectedItem property returns the entire object that your list is bound to. So say you've bound a list to a collection of Category objects (with each Category object having Name and ID properties). eg. ObservableCollection&l...
How to get Last record from Sqlite?
...
Try this:
SELECT *
FROM TABLE
WHERE ID = (SELECT MAX(ID) FROM TABLE);
OR
you can also used following solution:
SELECT * FROM tablename ORDER BY column DESC LIMIT 1;
...
How do I get SUM function in MySQL to return '0' if no values are found?
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Use COALESCE to avoid that outcome.
SELECT COALESCE(SUM(column),0)
FROM table
WHERE ...
To see it in action, please see this sql fiddle: http://www.sqlfiddle.com/#!2/d1542/3/0
More Information:
Given three tables (one with all numbers, one with all nul...
What's the difference between MyISAM and InnoDB? [duplicate]
... on the table, and while that lock is held, no other session can perform a SELECT or a DML operation on the table.
Those two specific engines you asked about (InnoDB and MyISAM) have different design goals. MySQL also has other storage engines, with their own design goals.
So, in choosing between In...
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 to get last N records with activerecord?
...e-wise - at least not up to Rails 3.1. SomeModel.last(5) will execute the select statement without a limit, returning all records of SomeModel to Ruby as an array, after which Ruby will pick out the last (5) elements. Efficiency-wise, currently, you want to use limit - particularly if you have pote...
Is there any way to create a blank solution (.sln) file first and then add projects?
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Creating Solutions To create a new
solution
On the File menu, select New and then click Project.
In the Project types pane, select Other Project Types and
then select Visual Studio
Solutions.
In the Templates pane, select Blank Solution.
Enter a name for the project.
To chan...
What's the recommended way to connect to MySQL from Go?
...l", store.user+":"+store.password+"@/"+store.database)
defer con.Close()
Select one row :
row := con.QueryRow("select mdpr, x, y, z from sometable where id=?", id)
cb := new(SomeThing)
err := row.Scan(&cb.Mdpr, &cb.X, &cb.Y, &cb.Z)
Select multiple rows and build an array with re...