大约有 41,000 项符合查询结果（耗时：0.0335秒） [XML]
Select values from XML field in SQL Server 2008
...
Given that the XML field is named 'xmlField'...
SELECT
[xmlField].value('(/person//firstName/node())[1]', 'nvarchar(max)') as FirstName,
[xmlField].value('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName
FROM [myTable]
...
Is there a way to access the “previous row” value in a SELECT statement?
...d to order by some column for this to be meaningful. Something like this:
select t1.value - t2.value from table t1, table t2
where t1.primaryKey = t2.primaryKey - 1
If you know how to order things but not how to get the previous value given the current one (EG, you want to order alphabetically) ...
LINQ query to select top five
...
var list = (from t in ctn.Items
where t.DeliverySelection == true && t.Delivery.SentForDelivery == null
orderby t.Delivery.SubmissionDate
select t).Take(5);
share
...
How can I select random files from a directory in bash?
I have a directory with about 2000 files. How can I select a random sample of N files through using either a bash script or a list of piped commands?
...
what is the difference between GROUP BY and ORDER BY in sql
... SUM, COUNT, AVG, etc).
TABLE:
ID NAME
1 Peter
2 John
3 Greg
4 Peter
SELECT *
FROM TABLE
ORDER BY NAME
=
3 Greg
2 John
1 Peter
4 Peter
SELECT Count(ID), NAME
FROM TABLE
GROUP BY NAME
=
1 Greg
1 John
2 Peter
SELECT NAME
FROM TABLE
GROUP BY NAME
HAVING Count(ID) > 1
=
Peter
...
How to check date of last change in stored procedure or function in SQL server
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SELECT name, create_date, modify_date
FROM sys.objects
WHERE type = 'P'
ORDER BY modify_date DESC
The type for a function is FN rather than P for procedure. Or you can filter on the name column.
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Can you build dynamic libraries for iOS and load them at runtime?
...e your own, separate dylib:
#include <dlfcn.h>
initWrapper() {
char *dylibPath = "/Applications/myapp.app/mydylib2.dylib";
void *libHandle = dlopen(dylibPath, RTLD_NOW);
if (libHandle != NULL) {
// This assumes your dylib’s init function is called init,
// ...
How to drop columns by name in a data frame
..."z","u"))]
x y
1 1 2
2 2 3
3 3 4
4 4 5
5 5 6
Or, much simpler, use the select argument of the subset function : you can then use the - operator directly on a vector of column names, and you can even omit the quotes around the names !
R> subset(df, select=-c(z,u))
x y
1 1 2
2 2 3
3 3 4
4 4 ...
How to create .ipa file using Xcode?
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In Xcode Version 10.0
Go to Window -> Organizer
Then select your app archive from archives
Then click the "Distribute App" button on right panel
Then follow the below steps
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6 : Finally select the place you want to sa...
resizes wrong; appears to have unremovable `min-width: min-content`
I have a <select> where one of its <option> ’s text values is very long. I want the <select> to resize so it is never wider than its parent, even if it has to cut off its displayed text. max-width: 100% should do that.
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