大约有 40,000 项符合查询结果（耗时：0.1001秒） [XML]
SQL: How to properly check if a record exists
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I would prefer not use Count function at all:
IF [NOT] EXISTS ( SELECT 1 FROM MyTable WHERE ... )
<do smth>
For example if you want to check if user exists before inserting it into the database the query can look like this:
IF NOT EXISTS ( SELECT 1 ...
include antiforgerytoken in ajax post ASP.NET MVC
... with ajax. I'm using ASP.NET MVC 3. I tried the solution in jQuery Ajax calls and the Html.AntiForgeryToken() . Using that solution, the token is now being passed:
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Extracting hours from a DateTime (SQL Server 2005)
...e #6 here blogs.sqlsentry.com/aaronbertrand/… and sqlblog.com/blogs/aaron_bertrand/archive/2011/09/20/…
– Aaron Bertrand
Oct 6 '14 at 19:44
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How to extract the year from a Python datetime object?
...se).
One key thing to note is that the time components can differ between 32-bit and 64-bit pythons in some python versions (2.5.x tree I think). So you will find things like hour/min/sec on some 64-bit platforms, while you get hour/minute/second on 32-bit.
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Django queries - id vs pk
...ry key field i.e. you don't need to care whether the primary key field is called id or object_id or whatever.
It also provides more consistency if you have models with different primary key fields.
share
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Leaflet - How to find existing markers, and delete markers?
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Should be a way to collect all of the layers used by Leaflet. :/
– jackyalcine
Aug 1 '12 at 21:39
10
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.toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])?
... the result may be different.
Benchmark results (score in microseconds, smaller = better):
Benchmark (n) Mode Samples Score Error Units
c.a.p.SO29378922.preSize 1 avgt 30 0.025 ▒ 0.001 us/op
c.a.p.SO29378922.preSize 100 avgt 30 0.15...
Coding Practices which enable the compiler/optimizer to make a faster program
...act.
Expect to be disappointed and to have to work very hard indeed for small performance improvements. Modern compilers for mature languages such as Fortran and C are very, very good. If you read an account of a 'trick' to get better performance out of code, bear in mind that the compiler writer...
Sql query to insert datetime in SQL Server
... I used the SQL query below to test the format, and it does indeed work in all SQL languages in sys.syslanguages:
declare @sql nvarchar(4000)
declare @LangID smallint
declare @Alias sysname
declare @MaxLangID smallint
select @MaxLangID = max(langid) from sys.syslanguages
set @LangID = 0
while @...
Rename multiple files in a directory in Python [duplicate]
...e script itself. Instead of using . as the dir, you could make a variable called dir and use that, then prepend dir to the filename.
– styfle
May 18 '11 at 5:53
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