大约有 43,000 项符合查询结果（耗时：0.0728秒） [XML]
Long vs Integer, long vs int, what to use and when?
...//docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html
byte, char .. 1B .. 8b
short int .. 2B .. 16b
int .. .. .. .. 4B .. 32b
long int .. 8B .. 64b
C .. just mess: https://en.wikipedia.org/wiki/C_data_types
short .. .. 16b
int .. .. .. 16b ... wtf?!?!
long .. .. 32b
long long .. ...
Select all columns except one in MySQL?
I'm trying to use a select statement to get all of the columns from a certain MySQL table except one. Is there a simple way to do this?
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How do you use script variables in psql?
...t myvariable value
... and can then be substituted, for example, as ...
SELECT * FROM :myvariable.table1;
... or ...
SELECT * FROM table1 WHERE :myvariable IS NULL;
edit: As of psql 9.1, variables can be expanded in quotes as in:
\set myvariable value
SELECT * FROM table1 WHERE column1 ...
Regular expression to allow spaces between words
...
tl;dr
Just add a space in your character class.
^[a-zA-Z0-9_ ]*$
Now, if you want to be strict...
The above isn't exactly correct. Due to the fact that * means zero or more, it would match all of the following cases that one would not usually mea...
What is the worst real-world macros/pre-processor abuse you've ever come across?
...efine static
#define void int
#define main(x) main()
struct F{void println(char* s){std::cout << s << std::endl;}};
struct S{F out;};
public static void main(String[] args) {
System.out.println("Hello World!");
}
Challenge: Can anyone do it with fewer defines and structs? ;-)
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Join vs. sub-query
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@JinghuiNiu Customers who bought expensive items: select custid from cust join bought using (custid) where price > 500. If a customer bought multiple expensive items, you'll get double-ups. To fix this, select custid from cust where exists (select * from bought where cust...
How can I remove the first line of a text file using bash/sed script?
... of magnitude. I'm testing it on a file of 500,000K lines (no more than 50 chars per line). However, I then realized I was using the FreeBSD version of tail (which comes with OS X by default). When I switched to GNU tail, the tail call was 10 times faster than the sed call (and the GNU sed call, too...
Can we pass parameters to a view in SQL?
..., like:
CREATE FUNCTION v_emp (@pintEno INT)
RETURNS TABLE
AS
RETURN
SELECT * FROM emp WHERE emp_id=@pintEno;
This allows you to use it as a normal view, with:
SELECT * FROM v_emp(10)
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Run PostgreSQL queries from the command line
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psql -U username -d mydatabase -c 'SELECT * FROM mytable'
If you're new to postgresql and unfamiliar with using the command line tool psql then there is some confusing behaviour you should be aware of when you've entered an interactive session.
For example, ...
Search for selection in vim
...
Check this Vim tip: Search for visually selected text
Or you can simply yank the selected text with y and go to search mode /, then you can paste the last yanked text with Ctrl+R 0
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