大约有 43,000 项符合查询结果(耗时:0.0430秒) [XML]
The cast to value type 'Int32' failed because the materialized value is null
...
where u.ID == userID
select (int?)ch.Amount).Sum() ?? 0;
This first casts to int? to tell the C# compiler that this expression can indeed return null, even though Sum() returns an int. Then we use the normal ?? operator to handle the null case....
How can you do paging with NHibernate?
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This performs a SELECT TOP query in SQL Server. Try it with SetFirstResult(1).SetMaxResult(2);
– Chris S
Feb 8 '09 at 17:02
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iOS 7.0 No code signing identities found
...ourcompanyName.Something (Put same as in AppId)
CodeSigningIdentity.
Select The Provisioning profile which you created.
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const vs constexpr on variables
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Are you sure? Because const int N = 10; char a[N]; works, and array bounds must be compile-time constants.
– fredoverflow
Nov 12 '12 at 16:22
10
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How do write IF ELSE statement in a MySQL query
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You probably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case when (action = 2 and state = 0)
THEN
1
ELSE
0
END)
as state from tbl1;
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@Override is not allowed when implementing interface method
...In JIdea 2020.1.2 and above,
Go to Project Structure [ Ctrl+Alt+Shift+S
]
Select Modules sub section
Select each module
Under sources-section, check Language Level
Change the Language Level as required
NOTE:
If you get below error after this change,
Error:java: Compilation failed: internal java c...
How are software license keys generated?
...ype in.
We must be able to blacklist (revoke) a license key in the case of chargebacks or purchases with stolen credit cards.
No “phoning home” to test keys. Although this practice is becoming more and more prevalent, I still do not appreciate it as a user, so will not ask my users to put up wi...
Xcode “The private key for is not installed on this mac - distributing”
...ychain Access on the machine that was used to generate the private keys
2. Select Keychains->Login and Category->Certificates on the left hand side
3. Locate the two certificates iPhone Developer: [your developer name] and iPhone Distribution: [your developer name]
4. Select both, right click...
Update Angular model after setting input value with jQuery
...to trigger('input') after input.val() the ng-change event fires after user selects calendar date. Thanks!
– Drone Brain
Oct 3 '13 at 20:07
3
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How to find a table having a specific column in postgresql
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you can query system catalogs:
select c.relname
from pg_class as c
inner join pg_attribute as a on a.attrelid = c.oid
where a.attname = <column name> and c.relkind = 'r'
sql fiddle demo
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