大约有 41,000 项符合查询结果（耗时：0.0547秒） [XML]
T-SQL CASE Clause: How to specify WHEN NULL
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Given your query you can also do this:
SELECT first_name + ' ' + ISNULL(last_name, '') AS Name FROM dbo.person
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MySQL string replace
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Yes, MySQL has a REPLACE() function:
mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww');
-> 'WwWwWw.mysql.com'
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_replace
Note that it's easier if you make that an alias when using SELECT
SEL...
Return empty cell from formula in Excel
...a by changing SomeRange to Range("MyRange"). To set a name for your cells, select the cells, click Define Name on the Formulas tab of the ribbon, and enter "MyRange" in the Name field. (And of course you could replace MyRange with anything you want.)
– devuxer
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Unicode, UTF, ASCII, ANSI format differences
...ny other places, it means UTF-8. Properly, Unicode refers to the abstract character set itself, not to any particular encoding.
UTF-16: 2 bytes per "code unit". This is the native format of strings in .NET, and generally in Windows and Java. Values outside the Basic Multilingual Plane (BMP) are enc...
How to remove selected commit log entries from a Git repository while keeping their changes?
I would like to remove selected commit log entries from a linear commit tree, so that the entries do not show in the commit log.
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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), ...
SQL Server Management Studio, how to get execution time down to milliseconds
...able in your proc:
DECLARE @EndTime datetime
DECLARE @StartTime datetime
SELECT @StartTime=GETDATE()
-- Write Your Query
SELECT @EndTime=GETDATE()
--This will return execution time of your query
SELECT DATEDIFF(ms,@StartTime,@EndTime) AS [Duration in millisecs]
AND see this
Measuring Quer...
postgresql list and order tables by size
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select table_name, pg_relation_size(quote_ident(table_name))
from information_schema.tables
where table_schema = 'public'
order by 2
This shows you the size of all tables in the schema public if you have multiple schemas, y...
Why there is no ForEach extension method on IEnumerable?
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Couldn't you just use Select instead of your Apply method? It seems to me that applying an action to each element and yielding it is exactly what Select does. E.g. numbers.Select(n => n*2);
– rasmusvhansen
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How does virtual inheritance solve the “diamond” (multiple inheritance) ambiguity?
...virtual void eat(){ std::cout<<"EAT=>D";} };
int main(int argc, char ** argv){
A *a = new D();
a->eat();
delete a;
}
... that way the output is gonna be the correct one: "EAT=>D"
Virtual inheritance only solves the duplication of the grandfather!
BUT you still need ...