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Remove duplicate rows in MySQL
...owing columns:
employee (id, first_name, last_name, start_date, ssn)
In order to delete the rows with a duplicate ssn column, and keeping only the first entry found, the following process can be followed:
-- create a new tmp_eployee table
CREATE TABLE tmp_employee LIKE employee;
-- add a unique...
Failed to Attach to Process ID Xcode
... cannot resolve localhost: Unknown host something is screwed up with your /etc/hosts file, go to Step 2
Step2: Check /etc/hosts
Check that the top of your /etc/hosts file looks like this
127.0.0.1 localhost
255.255.255.255 broadcasthost
::1 localhost
fe80::1%lo0 localhost
If ...
Unable to understand useCapture parameter in addEventListener
...g ("capture"), and at the end ("bubble").
Events are executed in the order of how they're defined. Say, you define 4 event listeners:
window.addEventListener("click", function(){console.log(1)}, false);
window.addEventListener("click", function(){console.log(2)}, true);
window.addEventL...
boolean in an if statement
...ample. It has to do with how Javascript does automatic type conversion in order to compare two values of different types.
– jfriend00
Dec 3 '19 at 16:17
Using helpers in model: how do I include helper dependencies?
...
To access helpers from your own controllers, just use:
OrdersController.helpers.order_number(@order)
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The type must be a reference type in order to use it as parameter 'T' in the generic type or method
...koverflow.com%2fquestions%2f6451120%2fthe-type-must-be-a-reference-type-in-order-to-use-it-as-parameter-t-in-the-gen%23new-answer', 'question_page');
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How do I delete a fixed number of rows with sorting in PostgreSQL?
...DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly, a row's ctid will change if it is...
What are good examples of genetic algorithms/genetic programming solutions? [closed]
...nute-by-minute price data of the S&P500 futures, as well as a specific order (buy or sell) and stop-loss and stop-profit amounts. Each string (or "gene") had its profit performance evaluated by a run through 3 years of historical data; whenever the specified "shape" matched the historical data,...
How are 3D games so efficient? [closed]
... a completely full-featured hardware device which is unlikely to exist, in order to show off all the features of the API. But since the hardware doesn't actually exist, it runs on your CPU instead. That's much more inefficient than delegating to a graphics card -- hence your high CPU usage.
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Using .sort with PyMongo
...er", 1), ("date", -1)])
The reason why this has to be a list is that the ordering of the arguments matters and dicts are not ordered in Python < 3.6
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