大约有 40,000 项符合查询结果（耗时：0.0448秒） [XML]
Max return value if empty query
...oeSize = Workers.Where(x => x.CompanyId == 8)
.Select(x => x.ShoeSize)
.DefaultIfEmpty(0)
.Max();
The zero in DefaultIfEmpty is not necessary.
...
When should I use a composite index?
...nefit a query that uses those fields for joining, filtering, and sometimes selecting. It will also benefit queries that use left-most subsets of columns in that composite. So the above index will also satisfy queries that need
index( column_A, column_B, column_C )
index( column_A, column_B )
index(...
What's the false operator in C# good for?
...he operator false declared in T, and T.&(x, y) is an invocation of the selected operator &. In other words, x is first evaluated and operator false is invoked on the result to determine if x is definitely false. Then, if x is definitely false, the result of the operation is the value previou...
How do you perform a left outer join using linq extension methods
...=> bar.Foo_Id,
(x,y) => new { Foo = x, Bars = y })
.SelectMany(
x => x.Bars.DefaultIfEmpty(),
(x,y) => new { Foo=x.Foo, Bar=y});
share
|
improve t...
How to write UPDATE SQL with Table alias in SQL Server 2008?
... Mark Byers - Great Answer!! This syntax allows me to add a commented out Select statement, which allows me to test the update by doing the select first (highlight from the select down and execute): SET Q.TITLE = 'TEST' -- SELECT *
– user1636464
Aug 30 '12 at ...
How can I view live MySQL queries?
... As far as I can tell, there is no way to trigger anything on a SELECT statement. Triggers only apply to INSERT, UPDATE, DELETE... or am I misinformed?
– gabe.
Dec 8 '11 at 21:14
...
How to create a sequence of integers in C#?
...
Linq projection with the rarely used indexer overload (i):
(new int[11]).Select((o,i) => i)
I prefer this method for its flexibilty.
For example, if I want evens:
(new int[11]).Select((item,i) => i*2)
Or if I want 5 minute increments of an hour:
(new int[12]).Select((item,i) => i*5...
Use tab to indent in textarea
...which;
if (keyCode == 9) {
e.preventDefault();
var start = this.selectionStart;
var end = this.selectionEnd;
// set textarea value to: text before caret + tab + text after caret
$(this).val($(this).val().substring(0, start)
+ "\t"
+ $(this).val...
How can I force Powershell to return an array when a call only returns one object?
...wmi Win32_NetworkAdapterConfiguration
| Where { $_.IPAddress }
| Select -Expand IPAddress
| Where { $_ -like '*.*.*.*' }
| Sort)
Specify the data type of the variable as an array:
[array]$serverIps = gwmi Win32_NetworkAdapterConfiguration
| Where { $_.IPAddress }
| S...
Linq with group by having count
...
from c in db.Company
group c by c.Name into grp
where grp.Count() > 1
select grp.Key
Or, using the method syntax:
Company
.GroupBy(c => c.Name)
.Where(grp => grp.Count() > 1)
.Select(grp => grp.Key);
...