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Adding 'serial' to existing column in Postgres
...int, b text);
CREATE TABLE bar (a serial, b text);
INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM generate_series(1, 5) i;
-- blocks of commands to turn foo into bar
CREATE SEQUENCE foo_a_seq;
ALTER TABLE foo ALTER...
Replace non-ASCII characters with a single space
I need to replace all non-ASCII (\x00-\x7F) characters with a space. I'm surprised that this is not dead-easy in Python, unless I'm missing something. The following function simply removes all non-ASCII characters:
...
Ruby on Rails form_for select field with class
I am beating my head against the wall on this one. I want to make a simple select tag using the f.select tag but nothing I do works. I put an example below:
...
Python: json.loads returns items prefixing with 'u'
...ing a dummy string (for now) like the code below. My output comes out with character 'u' prefixing each item:
9 Answers
...
Ruby, remove last N characters from a string?
What is the preferred way of removing the last n characters from a string?
13 Answers
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Why do pthreads’ condition variable functions require a mutex?
...pthread_cond_wait(&cond); //imagine cond_wait did not have a mutex
char *data = some_data;
some_data = NULL;
handle(data);
}
you'd naturally get a lot of race condition, what if the other thread did some_data = new_data right after you got woken up, but before you did data = some_d...
SQL - Update multiple records in one query
...the rows u need using a small script.
UPDATE [Table]
SET couloumn1= (select couloumn1 FROM Table WHERE IDCouloumn = [PArent ID]),
couloumn2= (select couloumn2 FROM Table WHERE IDCouloumn = [PArent ID]),
couloumn3= (select couloumn3 FROM Table WHERE IDCouloumn = [PArent ID]),
cou...
Select where count of one field is greater than one
...clause, for aggregate result comparison.
Taking the query at face value:
SELECT *
FROM db.table
HAVING COUNT(someField) > 1
Ideally, there should be a GROUP BY defined for proper valuation in the HAVING clause, but MySQL does allow hidden columns from the GROUP BY...
Is this in preparati...
MySql Table Insert if not exist otherwise update
...p using:
replace into last_recogs (id, hasher_id, hash_id, last_recog)
select l.* from
(select id, hasher_id, hash_id, [new_value] from last_recogs
where hasher_id in (select id from hashers where name=[hasher_name])
and hash_id in (select id from hashes where name=[hash_name])
...
Uniq by object attribute in Ruby
What's the most elegant way to select out objects in an array that are unique with respect to one or more attributes?
14 An...