大约有 45,000 项符合查询结果（耗时：0.0343秒） [XML]
What is the worst gotcha in C# or .NET? [closed]
...Generic;
using System.Diagnostics;
class Test
{
static IEnumerable<char> CapitalLetters(string input)
{
if (input == null)
{
throw new ArgumentNullException(input);
}
foreach (char c in input)
{
yield return char.ToUpper(...
SQL JOIN and different types of JOINs
...
There are relatively new LATERAL JOIN .. SELECT * FROM r1, LATERAL fx(r1)
– Pavel Stehule
Jul 30 '13 at 11:52
13
...
How do I select an entire row which has the largest ID in the table?
...
You could use a subselect:
SELECT row
FROM table
WHERE id=(
SELECT max(id) FROM table
)
Note that if the value of max(id) is not unique, multiple rows are returned.
If you only want one such row, use @MichaelMior's answer,
SELEC...
How to convert std::string to NSString?
...even fairly straightforward NSString content --- for instance, punctuation characters with a bidirectional encoding. */
– cyrilchampier
Nov 4 '12 at 15:14
...
How do SQL EXISTS statements work?
... criteria -- this is why it can be faster than IN. Also be aware that the SELECT clause in an EXISTS is ignored - IE:
SELECT s.*
FROM SUPPLIERS s
WHERE EXISTS (SELECT 1/0
FROM ORDERS o
WHERE o.supplier_id = s.supplier_id)
...should hit a division by zero error...
SQL WHERE.. IN clause multiple columns
...a derived table from the subquery, and join table1 to this derived table:
select * from table1 LEFT JOIN
(
Select CM_PLAN_ID, Individual_ID
From CRM_VCM_CURRENT_LEAD_STATUS
Where Lead_Key = :_Lead_Key
) table2
ON
table1.CM_PLAN_ID=table2.CM_PLAN_ID
AND table1.Individual=table2.Indi...
How to select rows with no matching entry in another table?
...
Here's a simple query:
SELECT t1.ID
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.ID = t2.ID
WHERE t2.ID IS NULL
The key points are:
LEFT JOIN is used; this will return ALL rows from Table1, regardless of whether or not there is a matching row i...
Signed to unsigned conversion in C - is it always safe?
... need to subtract the given number from max value (256 in case of unsigned char)? For example: 140 when converted to signed number becomes -116. But 20 becomes 20 itself. So any easy trick here?
– Jon Wheelock
Oct 18 '15 at 14:01
...
Left-pad printf with spaces
...
If you want the word "Hello" to print in a column that's 40 characters wide, with spaces padding the left, use the following.
char *ptr = "Hello";
printf("%40s\n", ptr);
That will give you 35 spaces, then the word "Hello". This is how you format stuff when you know how wide you wa...
Working with select using AngularJS's ng-options
...o work... note the ng-model="blah" which is saying "set $scope.blah to the selected value".
Try this:
<select ng-model="blah" ng-options="item.ID as item.Title for item in items"></select>
Here's more from AngularJS's documentation (if you haven't seen it):
for array data sources...