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Select n random rows from SQL Server table
I've got a SQL Server table with about 50,000 rows in it. I want to select about 5,000 of those rows at random. I've thought of a complicated way, creating a temp table with a "random number" column, copying my table into that, looping through the temp table and updating each row with RAND() , and ...
Why does UITableViewCell remain highlighted?
...
In your didSelectRowAtIndexPath you need to call deselectRowAtIndexPath to deselect the cell.
So whatever else you are doing in didSelectRowAtIndexPath you just have it call deselectRowAtIndexPath as well.
- (void)tableView:(UITableVi...
PostgreSQL - fetch the row which has the Max value for a column
...sted index lookup into lives - on my machine
-- the latter query plan was selected given my memory settings and
-- histogram
SELECT
l1.*
FROM
lives AS l1
INNER JOIN (
SELECT
usr_id,
MAX(time_stamp) AS time_stamp_max
FROM
lives
GROUP BY
usr_id
) AS l2
...
What is this operator in MySQL?
...d <> both give UNKNOWN with NULL on either side of the expression.)
SELECT *
FROM table
WHERE YourColumn IS NOT NULL;
can also negate the null safe equality operator but this is not standard SQL.
SELECT *
FROM table
WHERE NOT (YourColumn <=> NULL);
...
Generating random numbers in Objective-C
...
arc4random_stir(void);
void
arc4random_addrandom(unsigned char *dat, int datlen);
DESCRIPTION
The arc4random() function uses the key stream generator employed by the arc4 cipher, which uses 8*8 8
bit S-Boxes. The S-Boxes can be in about (2**1700) states. The arc4random(...
Are PDO prepared statements sufficient to prevent SQL injection?
....
$pdo->query('SET NAMES gbk');
$var = "\xbf\x27 OR 1=1 /*";
$query = 'SELECT * FROM test WHERE name = ? LIMIT 1';
$stmt = $pdo->prepare($query);
$stmt->execute(array($var));
In certain circumstances, that will return more than 1 row. Let's dissect what's going on here:
Selecting a Cha...
RESTful Authentication
...REST. Since we allow communication not only over HTTP/1.1, but also named pipes or GDI messages (locally), we tried to implement a truly RESTful authentication pattern, and not rely on HTTP specificity (like header or cookies).
Later Note: adding a signature in the URI can be seen as bad practice (...
How to get value of selected radio button?
I want to get the selected value from a group of radio buttons.
28 Answers
28
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Distinct in Linq based on only one field of the table
...
Try this:
table1.GroupBy(x => x.Text).Select(x => x.FirstOrDefault());
This will group the table by Text and use the first row from each groups resulting in rows where Text is distinct.
...
Android ViewPager with bottom dots
...droid:layout_height="wrap_content"
app:tabBackground="@drawable/tab_selector"
app:tabGravity="center"
app:tabIndicatorHeight="0dp"/>
</RelativeLayout>
Hook up your UI elements inactivity or fragment as follows:
Java Code:
mImageViewPager = (ViewPager) findViewById(R.id...