大约有 43,000 项符合查询结果（耗时：0.0299秒） [XML]
Is there any performance gain in indexing a boolean field?
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It depends on the actual queries and the selectivity of the index/query combination.
Case A: condition WHERE isok = 1 and nothing else there:
SELECT *
FROM tableX
WHERE isok = 1
If the index is selective enough (say you have 1M rows and only 1k have isok = 1), ...
Explicit vs implicit SQL joins
...e joined and how they are joined. Try compare larger SQL queries where you selecting from 8 different tables and you have lots of filtering in the where. By using join syntax you separate out the parts where the tables are joined, to the part where you are filtering the rows.
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How do I view the SQL generated by the Entity Framework?
...e query = from x in appEntities
where x.id == 32
select x;
var sql = ((System.Data.Objects.ObjectQuery)query).ToTraceString();
or in EF6:
var sql = ((System.Data.Entity.Core.Objects.ObjectQuery)query)
.ToTraceString();
That will give you the SQL that was g...
How can I selectively escape percent (%) in Python strings?
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>>> test = "have it break."
>>> selectiveEscape = "Print percent %% in sentence and not %s" % test
>>> print selectiveEscape
Print percent % in sentence and not have it break.
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Querying data by joining two tables in two database on different servers
...just prefixing the database name with the other server. I.E:
-- FROM DB1
SELECT *
FROM [MyDatabaseOnDB1].[dbo].[MyTable] tab1
INNER JOIN [DB2].[MyDatabaseOnDB2].[dbo].[MyOtherTable] tab2
ON tab1.ID = tab2.ID
Once the link is established, you can also use OPENQUERY to execute a SQL st...
ReactJS render string with non-breaking spaces
I have some props that has a string that could contain characters such as &.
It also contains spaces. I want to replace all spaces with   .
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How do you reverse a string in place in JavaScript?
...with a return statement, without using built-in functions ( .reverse() , .charAt() etc.)?
51 Answers
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Fold / Collapse the except code section in sublime text 2
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One thing you can do is select the Except code bloc using a regular expression, for instance using except(.|\n)*?raise.* in your case. You can then select "Find all" in the search bar, then Edit->Code Folding -> Fold .
Windows shortcut : Ctrl-...
iOS app with framework crashed on device, dyld: Library not loaded, Xcode 6 Beta
...r Products folder in your project.
Right click on your .framework and select "Show in Finder".
3) Place framework in your project
Drag and drop the .framework from your Finder window to your app project's "Framework" folder.
4) Configure app project for framework
Select the top leve...
Replace new lines with a comma delimiter with Notepad++?
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Open the find and replace dialog (press CTRL+H).
Then select Regular expression in the 'Search Mode' section at the bottom.
In the Find what field enter this: [\r\n]+
In the Replace with: ,
There is a space after the comma.
This will also replace lines like
Apples
Apri...