大约有 41,000 项符合查询结果（耗时：0.0153秒） [XML]
SQL Server: Make all UPPER case to Proper Case/Title Case
...lare @i int;
declare @c char(1);
if @Text is null
return null;
select @Reset = 1, @i = 1, @Ret = '';
while (@i <= len(@Text))
select @c = substring(@Text, @i, 1),
@Ret = @Ret + case when @Reset = 1 then UPPER(@c) else LOWER(@c) end,
@Reset = case when @c like '[a-zA...
How to get first character of a string in SQL?
...
SELECT SUBSTR(thatColumn, 1, 1) As NewColumn from student
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Is there a way of making strings file-path safe in c#?
...id chars and an _ for invalid ones
var validFilename = new string(filename.Select(ch => invalidFileNameChars.Contains(ch) ? '_' : ch).ToArray());
To replace invalid characters (and avoid potential name conflict like Hell* vs Hell$):
static readonly IList<char> invalidFileNameChars = Path...
Comparing Dates in Oracle SQL
...r by using the built-in TO_DATE() function, or a date literal.
TO_DATE()
select employee_id
from employee
where employee_date_hired > to_date('31-DEC-95','DD-MON-YY')
This method has a few unnecessary pitfalls
As a_horse_with_no_name noted in the comments, DEC, doesn't necessarily mean D...
How important is the order of columns in indexes?
I've heard that you should put columns that will be the most selective at the beginning of the index declaration. Example:
...
How can I reliably get an object's address when operator& is overloaded?
...on operator that the type comes with.
Thus the f(T&,long) overload is selected (and the Integral Promotion performed).
What happens for any other type ?
Thus the f(T&,long) overload is selected, because there the type does not match the T* parameter.
Note: from the remarks in the fil...
Listing all permutations of a string/integer
...(IEnumerable<T> list, int length)
{
if (length == 1) return list.Select(t => new T[] { t });
return GetPermutations(list, length - 1)
.SelectMany(t => list.Where(e => !t.Contains(e)),
(t1, t2) => t1.Concat(new T[] { t2 }));
}
Example:
IEnumerable<...
SQL SERVER: Get total days between two dates
...:09.3312722';
DECLARE @enddate datetime2 = '2009-05-04 12:10:09.3312722';
SELECT DATEDIFF(day, @startdate, @enddate);
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Left Join With Where Clause
...ring away rows where the left join doesn't succeed. Move it to the join:
SELECT `settings`.*, `character_settings`.`value`
FROM `settings`
LEFT JOIN
`character_settings`
ON `character_settings`.`setting_id` = `settings`.`id`
AND `character_settings`.`character_id` = '1'
...
SQL SELECT speed int vs varchar
...k: A=261MB B=292MB C=322MB
Non-indexed by id: select count(*), select by id: 450ms same on all tables
Insert* one row per TX: B=9ms/record C=9ms/record
Bulk insert* in single TX: B=140usec/record C=180usec/record
Indexed by id, select by id: B=about 2...