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SQL query return data from multiple tables
...l auto_increment primary key,
-> color varchar(15), paint varchar(10));
Query OK, 0 rows affected (0.01 sec)
mysql> show columns from colors;
+-------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------...
The cast to value type 'Int32' failed because the materialized value is null
...where there can be unexpected nulls in different places. ...DefaultIfEmpty(0).Sum(0) can help in this (quite simple) case, where there might be no elements and sql's SUM returns null whereas c# expect 0.
A more general approach is to use ?? which will be translated to COALESCE whenever there is a r...
How are multi-dimensional arrays formatted in memory?
...things are going to happen. Here's a quick example:
int array1[3][2] = {{0, 1}, {2, 3}, {4, 5}};
In memory looks like this:
0 1 2 3 4 5
exactly the same as:
int array2[6] = { 0, 1, 2, 3, 4, 5 };
But if you try to pass array1 to this function:
void function1(int **a);
you'll get a warnin...
Value of i for (i == -i && i != 0) to return true in Java
....toBinaryString(Integer.MIN_VALUE));
you see that Integer.MIN_VALUE is
10000000000000000000000000000000
Taking the negative value is done by first swapping 0 and 1, which gives
01111111111111111111111111111111
and by adding 1, which gives
10000000000000000000000000000000
As you can see in...
Does pandas iterrows have performance issues?
...ateen Ulhaq
16.6k1111 gold badges6464 silver badges105105 bronze badges
answered Jul 21 '14 at 17:39
JeffJeff
100k1717 gold badges...
Finding Number of Cores in Java
... |
edited Nov 17 '11 at 9:03
answered Jan 21 '11 at 13:58
d...
How do I reverse a C++ vector?
...{
std::vector<int> a;
std::reverse(a.begin(), a.end());
return 0;
}
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Best way to find if an item is in a JavaScript array? [duplicate]
...
As of ECMAScript 2016 you can use includes()
arr.includes(obj);
If you want to support IE or other older browsers:
function include(arr,obj) {
return (arr.indexOf(obj) != -1);
}
EDIT:
This will not work on IE6, 7 or 8 though. The be...
Test if a command outputs an empty string
...r success, non-zero for failure). For example:
files=$(ls -A)
if [[ $? != 0 ]]; then
echo "Command failed."
elif [[ $files ]]; then
echo "Files found."
else
echo "No files found."
fi
More info here.
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