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In SQL, what's the difference between count(column) and count(*)?
...a values(null,1)
insert #bla values(1,null)
insert #bla values(null,null)
select count(*),count(id),count(id2)
from #bla
results
7 3 2
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updating table rows in postgres using subquery
...ery.customer,
address=subquery.address,
partn=subquery.partn
FROM (SELECT address_id, customer, address, partn
FROM /* big hairy SQL */ ...) AS subquery
WHERE dummy.address_id=subquery.address_id;
This syntax is not standard SQL, but it is much more convenient for this type of query...
How to split a string literal across multiple lines in C / Objective-C?
...de it.
#define QUOTE(...) #__VA_ARGS__
const char *sql_query = QUOTE(
SELECT word_id
FROM table1, table2
WHERE table2.word_id = table1.word_id
ORDER BY table1.word ASC
);
the preprocessor turns this into:
const char *sql_query = "SELECT word_id FROM table1, table2 WHERE table2.wo...
Beautiful Soup and extracting a div and its contents by ID
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Beautiful Soup 4 supports most CSS selectors with the .select() method, therefore you can use an id selector such as:
soup.select('#articlebody')
If you need to specify the element's type, you can add a type selector before the id selector:
soup.select('di...
Visual Studio 2013 hangs when opening a solution
...| Attach to Process...
In the list of processes locate devenv.exe.
Click Select... and explicitly choose 'Native' and 'Managed' code.
Click OK and OK to close Select dialog and Attach to Process dialog.
Go back to the first instance of VS and repro the hang.
Upon the hang, control should go to ...
CSS Child vs Descendant selectors
I am a bit confused between these 2 selectors.
8 Answers
8
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Strange SQLAlchemy error message: TypeError: 'dict' object does not support indexing
...
This should be the selected answer. It solved the issue in my case.
– Gani Simsek
Feb 20 '17 at 13:11
1
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How to remove a Gitlab project?
...
Go to the project page
Select "Settings"
Select the "General" section (you must be in the repository you want to delete to delete it)
If you have enough rights, then at the bottom of the page will be a button for "Advanced settings" (i.e. project s...
How to set timeout on python's socket recv method?
...
The typical approach is to use select() to wait until data is available or until the timeout occurs. Only call recv() when data is actually available. To be safe, we also set the socket to non-blocking mode to guarantee that recv() will never block indef...
Modifying a subset of rows in a pandas dataframe
...The df.A==0 expression creates a boolean series that indexes the rows, 'B' selects the column. You can also use this to transform a subset of a column, e.g.:
df.loc[df.A==0, 'B'] = df.loc[df.A==0, 'B'] / 2
I don't know enough about pandas internals to know exactly why that works, but the basic is...