大约有 12,000 项符合查询结果（耗时：0.0181秒） [XML]
Modify table: How to change 'Allow Nulls' attribute from not null to allow null
...
I wrote this so I could edit all tables and columns to null at once:
select
case
when sc.max_length = '-1' and st.name in ('char','decimal','nvarchar','varchar')
then
'alter table [' + so.name + '] alter column [' + sc.name + '] ' + st.name + '(MAX) NULL'
when st.name in ('char','decimal','n...
Are there any disadvantages to always using nvarchar(MAX)?
...E @SomeString NVARCHAR(10),
@StartTime DATETIME;
--=====
SELECT @startTime = GETDATE();
SELECT TOP 1000000
@SomeString = 'ABC'
FROM master.sys.all_columns ac1,
master.sys.all_columns ac2;
SELECT testTime='10', Duration = DATEDIFF(ms,@StartTime,GETDATE());
GO
--...
Division of integers in Java [duplicate]
...st be floating point number
1/10 = 0
1.0/10 = 0.1
1/10.0 = 0.1
Just type cast either of them.
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How do I use Linq to obtain a unique list of properties from a list of objects?
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IEnumerable<int> ids = list.Select(x=>x.ID).Distinct();
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How can I easily convert DataReader to List? [duplicate]
... writing an extension method for this:
public static IEnumerable<T> Select<T>(this IDataReader reader,
Func<IDataReader, T> projection)
{
while (reader.Read())
{
yield return projection(reader);
}
}
You can then use LINQ...
Call to undefined method mysqli_stmt::get_result
...the code becomes:
include 'conn.php';
$conn = new Connection();
$query = 'SELECT EmailVerified, Blocked FROM users WHERE Email = ? AND SLA = ? AND `Password` = ?';
$stmt = $conn->mysqli->prepare($query);
$stmt->bind_param('sss', $_POST['EmailID'], $_POST['SLA'], $_POST['Password']);
$stmt-...
C# 'is' operator performance
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Using is can hurt performance if, once you check the type, you cast to that type. is actually casts the object to the type you are checking so any subsequent casting is redundant.
If you are going to cast anyway, here is a better approach:
ISpecialType t = obj as ISpecialType;
if (t ...
Converting a double to an int in C#
... that is, 4.5 is converted to 4, and 5.5 is converted to 6.
...while the cast truncates:
When you convert from a double or float value to an integral type, the
value is truncated.
Update: See Jeppe Stig Nielsen's comment below for additional differences (which however do not come into play...
Undefined reference to static class member
...question. The second part is much more interesting: Why does adding a NOP cast make it work without requiring the external declaration?
– Brent Bradburn
Feb 1 '11 at 0:48
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Convert Decimal to Double
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An explicit cast to double like this isn't necessary:
double trans = (double) trackBar1.Value / 5000.0;
Identifying the constant as 5000.0 (or as 5000d) is sufficient:
double trans = trackBar1.Value / 5000.0;
double trans = trackBar1...