大约有 40,000 项符合查询结果（耗时：0.0399秒） [XML]
'IF' in 'SELECT' statement - choose output value based on column values
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SELECT id,
IF(type = 'P', amount, amount * -1) as amount
FROM report
See http://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html.
Additionally, you could handle when the condition is null. In the case of...
How to get sp_executesql result into a variable?
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DECLARE @ParmDefinition nvarchar(500);
DECLARE @tablename nvarchar(50)
SELECT @tablename = N'products'
SELECT @sSQL = N'SELECT @retvalOUT = MAX(ID) FROM ' + @tablename;
SET @ParmDefinition = N'@retvalOUT int OUTPUT';
EXEC sp_executesql @sSQL, @ParmDefinition, @retvalOUT=@retval OUTPUT;
SE...
Is bool a native C type?
...goto
if
int
long
register
return
short
signed
static
struct
switch
typedef
union
unsigned
void
volatile
while
Here's an article discussing some other differences with C as used in the kernel and the standard: http://www.ibm.com/developerworks/linux/library/l-gcc-hacks/index.html
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Can you have if-then-else logic in SQL? [duplicate]
I need to do select data from a table based on some kind of priority like so:
7 Answers
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TLSF源码及算法介绍 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...*/
/* bit 1 allows to know whether the previous block is free */
union {
struct free_ptr_struct free_ptr;
u8_t buffer[1]; /*sizeof(struct free_ptr_struct)]; */
} ptr;
} bhdr_t;
/* This structure is embedded at the beginning of each area, giving us
* eno...
What are the most common naming conventions in C?
...function names, hardly ever do you see camel case in C;
structs, typedefs, unions, members (of unions and structs) and enum values typically are in lower case (in my experience) rather than the C++/Java/C#/etc convention of making the first letter a capital but I guess it's possible in C too.
C++ ...
When should I use cross apply over inner join?
...APPLY works better on things that have no simple JOIN condition.
This one selects 3 last records from t2 for each record from t1:
SELECT t1.*, t2o.*
FROM t1
CROSS APPLY
(
SELECT TOP 3 *
FROM t2
WHERE t2.t1_id = t1.id
ORDER BY
t2.ran...
Inserting multiple rows in mysql
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it's also possible to use INSERT INTO Table SELECT 1, '14/05/2012', 3 UNION SELECT 2, '05/14/2012', 3. of course, this will only be better of the inserted values are coming from different tables.
– Zohar Peled
Jun 1 '15 at 9:18
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What makes a SQL statement sargable?
...non-sargable is to include a field inside a function in the where clause:
SELECT ... FROM ...
WHERE Year(myDate) = 2008
The SQL optimizer can't use an index on myDate, even if one exists. It will literally have to evaluate this function for every row of the table. Much better to use:
WHERE myDat...
What is the leading LINQ for JavaScript library? [closed]
... different names (in fact, they have more traditional names than in Linq). Select becomes map, Where becomes filter, First and FirstOrDefault become [0].
Almost no library I know of (including I think the ones you linked to) bother to make the implementation lazy as in .NET Linq, they just evaluate...