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Is having an 'OR' in an INNER JOIN condition a bad idea?
...o improve the speed of an immensely slow query (several minutes on two tables with only ~50,000 rows each, on SQL Server 2008 if it matters), I narrowed down the problem to an OR in my inner join, as in:
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C语言结构体里的成员数组和指针 - C/C++ - 清泛网 - 专注C/C++及内核技术
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struct test t;
我们用gdb跟进去，对于实例t，我们可以看到：
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# t实例中的p就是一个野指针
(gdb) p t
$1 = {i = 0, c = 0 '\000', d = 0...
Fetch the row which has the Max value for a column
Table:
35 Answers
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How does Activity.finish() work in Android?
...lled finish() will run to completion. The finish() operation will not even begin until you return control to Android.
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PostgreSQL: Can you create an index in the CREATE TABLE definition?
I want to add indexes to some of the columns in a table on creation. Is there are way to add them to the CREATE TABLE definition or do I have to add them afterward with another query?
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Which iomanip manipulators are 'sticky'?
I recently had a problem creating a stringstream due to the fact that I incorrectly assumed std::setw() would affect the stringstream for every insertion, until I changed it explicitly. However, it is always unset after the insertion.
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When should you not use virtual destructors?
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There is no need to use a virtual destructor when any of the below is true:
No intention to derive classes from it
No instantiation on the heap
No intention to store in a pointer of a superclass
No specific reason to avoid it unless you are really so pressed for memory.
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How to keep a git branch in sync with master
At the moment git is doing my head in, I cannot come up with the best solution for the following.
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Count number of objects in list [closed]
R function that will return the number of items in a list?
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How to catch integer(0)?
...of printing a zero length vector (an integer one), so you could test for a being of length 0:
R> length(a)
[1] 0
It might be worth rethinking the strategy you are using to identify which elements you want, but without further specific details it is difficult to suggest an alternative strategy....