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MySQL SELECT WHERE datetime matches day (and not necessarily time)
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NEVER EVER use a selector like DATE(datecolumns) = '2012-12-24' - it is a performance killer:
it will calculate DATE() for all rows, including those, that don't match
it will make it impossible to use an index for the query
It is much fas...
Delete duplicate rows from small table
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DELETE FROM dupes a
WHERE a.ctid <> (SELECT min(b.ctid)
FROM dupes b
WHERE a.key = b.key);
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Cannot simply use PostgreSQL table name (“relation does not exist”)
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In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to th...
Selecting text in an element (akin to highlighting with your mouse)
I would like to have users click a link, then it selects the HTML text in another element ( not an input).
16 Answers
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Why does HTML think “chucknorris” is a color?
...om the blog post, we get the following:
Replace all nonvalid hexadecimal characters with 0's
chucknorris becomes c00c0000000
Pad out to the next total number of characters divisible by 3 (11 -> 12)
c00c 0000 0000
Split into three equal groups, with each component representing the correspond...
jQuery selector regular expressions
...d or regular expressions (not sure on the exact terminology) with a jQuery selector.
10 Answers
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MySQL combine two columns into one column
...does not start with a digit, then the converted value is 0.
So try this:
select concat(column1, column2)
Two ways to add a space:
select concat(column1, ' ', column2)
select concat_ws(' ', column1, column2)
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How is the “greater than” or “>” character used in CSS?
I have seen this character a number of times in CSS files but I have no idea how its used. Can anyone explain it to me and show how they are useful in making a page style easier?
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Length of an integer in Python
...h of an integer.
def libc_size(i):
return libc.snprintf(buf, 100, c_char_p(b'%i'), i) # equivalent to `return snprintf(buf, 100, "%i", i);`
def str_size(i):
return len(str(i)) # Length of `i` as a string
def math_size(i):
return 1 + math.floor(math.log10(i)) # 1 + floor of log10 of ...
What is the purpose of base 64 encoding and why it used in HTTP Basic Authentication?
...oding. It's a way of representing binary data using only printable (text) characters.
See this paragraph from the wikipedia page for HTTP Basic Authentication:
While encoding the user name and password with the Base64 algorithm typically makes them unreadable by the naked eye, they are as easi...