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What is the error “Every derived table must have its own alias” in MySQL?
...hout their names (or aliases) so, you must give unique names (aliases) for all of your sub-queries to make dbms query engine make it's work properly."
– Bahadir Tasdemir
Apr 25 '16 at 7:33
...
What is the maximum value for an int32?
...bout 1 billion. One of the 32 bits is used for sign, so the max value is really only 2^31, which is about twice the amount you get for 2^(3*10): 2 billion.
– 16807
Dec 3 '13 at 22:24
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Getting the docstring from a function
...
On ipython or jupyter notebook, you can use all the above mentioned ways, but i go with
my_func?
or
?my_func
for quick summary of both method signature and docstring.
I avoid using
my_func??
(as commented by @rohan) for docstring and use it only to check th...
How to remove all of the data in a table using Django
...
Inside a manager:
def delete_everything(self):
Reporter.objects.all().delete()
def drop_table(self):
cursor = connection.cursor()
table_name = self.model._meta.db_table
sql = "DROP TABLE %s;" % (table_name, )
cursor.execute(sql)
...
warning: [options] bootstrap class path not set in conjunction with -source 1.5
...000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C48.9099 6.97997 49.672 6.73443 49.672 5.93063C49.672 5.22043 48.9832 4.61182 48.1414 4.61182C47.4335 4.61182 46.7256 4.91628 46.0943 5.50789C45.7307 4.9328 4...
mingw-w64 threads: posix vs win32
I'm installing mingw-w64 on Windows and there are two options: win32 threads and posix threads. I know what is the difference between win32 threads and pthreads but I don't understand what is the difference between these two options. I doubt that if I will choose posix threads it will prevent me fro...
Why does “_” (underscore) match “-” (hyphen)?
...you are in a pattern context. e.g. inside a LIKE statement. When replacing all _ with an - : UPDATE sys_file set identifier = REPLACE(identifier, '_', '-') WHERE identifier LIKE '%\_%';. Notice the escaping inside LIKE and no escaping inside REPLACE. (I find it strange though that you are not in a p...
C语言结构体里的成员数组和指针 - c++1y / stl - 清泛IT社区，为创新赋能！
...; 0 0
0x601018: 32 16 96 0 0 0 0 0
(gdb) x /10b this->conte...
__getattr__ on a module
...
A while ago, Guido declared that all special method lookups on
new-style classes bypass __getattr__ and __getattribute__. Dunder methods had previously worked on modules - you could, for example, use a module as a context manager simply by defining __enter__...
When do you use the “this” keyword? [closed]
...declare extension methods
To pass parameters between constructors
To internally reassign value type (struct) value.
To invoke an extension method on the current instance
To cast itself to another type
To chain constructors defined in the same class
You can avoid the first usage by not having membe...