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Error when trying to obtain a certificate: The specified item could not be found in the keychain
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I solved it. Ensure you are in the "Certificates" section and you select "Apple Worldwide Developer Relations Certification Authority" before requesting a certificate.
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What is the difference between the states selected, checked and activated in Android?
...below added):
... For example, in a list view with single or multiple selection
enabled, the views in the current selection set are activated. (Um,
yeah, we are deeply sorry about the terminology here.) The activated
state is propagated down to children of the view it is set on.
So here...
SQL Server Profiler - How to filter trace to only display events from one database?
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Under Trace properties > Events Selection tab > select show all columns. Now under column filters, you should see the database name. Enter the database name for the Like section and you should see traces only for that database.
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Reshaping data.frame from wide to long format
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Here is another example showing the use of gather from tidyr. You can select the columns to gather either by removing them individually (as I do here), or by including the years you want explicitly.
Note that, to handle the commas (and X's added if check.names = FALSE is not set), I am also us...
Random record from MongoDB
...llection.
db.mycoll.aggregate([{ $sample: { size: 1 } }])
If you want to select the random document(s) from a filtered subset of the collection, prepend a $match stage to the pipeline:
// Get one random document matching {a: 10} from the mycoll collection.
db.mycoll.aggregate([
{ $match: { a:...
CROSS JOIN vs INNER JOIN in SQL
...ame situation.
These 2 examples will return the same result:
Cross join
select * from table1 cross join table2 where table1.id = table2.fk_id
Inner join
select * from table1 join table2 on table1.id = table2.fk_id
Use the last method
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Equals(=) vs. LIKE
... can produce results different from the = comparison operator:
mysql> SELECT 'ä' LIKE 'ae' COLLATE latin1_german2_ci;
+-----------------------------------------+
| 'ä' LIKE 'ae' COLLATE latin1_german2_ci |
+-----------------------------------------+
| 0 |...
SQL Group By with an Order By
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In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:
SELECT COUNT(id) AS theCount, `Tag` from `images-tags`
GROUP BY `Tag`
ORDER BY theCount DESC
LIMIT 20
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Get contentEditable caret index position
...tion(editableDiv) {
var caretPos = 0,
sel, range;
if (window.getSelection) {
sel = window.getSelection();
if (sel.rangeCount) {
range = sel.getRangeAt(0);
if (range.commonAncestorContainer.parentNode == editableDiv) {
caretPos = range.endOffset;
}
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MySQL ERROR 1045 (28000): Access denied for user 'bill'@'localhost' (using password: YES)
...=/tmp/mysql-5.5.sock
Welcome to the MySQL monitor (...)
mysql> SELECT user, host FROM mysql.user;
+------+-----------+
| user | host |
+------+-----------+
| bill | % |
| root | 127.0.0.1 |
| root | ::1 |
| root | localhost |
+------+---...