大约有 30,000 项符合查询结果（耗时：0.0383秒） [XML]
How do I insert NULL values using PDO?
...':param' => !empty($val) ? $val : null )); Use !empty because for empty string you would also want to set null in database
– Shehzad Nizamani
Jun 30 '17 at 19:36
1
...
Abstract classes in Swift Language
... the protocol extension.
protocol MyInterface {
func myMethod() -> String
}
extension MyInterface {
func myMethod() -> String {
fatalError("Not Implemented")
}
}
class MyConcreteClass: MyInterface {
func myMethod() -> String {
return "The output"
}...
How to delete from select in MySQL?
...ner subquery result (looks rather hacky, though):
DELETE FROM posts WHERE id IN (
SELECT * FROM (
SELECT id FROM posts GROUP BY id HAVING ( COUNT(id) > 1 )
) AS p
)
Or use joins as suggested by Mchl.
sh...
How do I perform the SQL Join equivalent in MongoDB?
... The new $lookup operator added to the aggregation pipeline is essentially identical to a left outer join:
https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup
From the docs:
{
$lookup:
{
from: <collection to join>,
localField: <fiel...
How do I get the first element from an IEnumerable in .net?
... to get the first item on any type IEnumerable.
Call it like so:
List<string> items = new List<string>() { "A", "B", "C", "D", "E" };
string firstItem = First<string>(items);
Or
int[] items = new int[] { 1, 2, 3, 4, 5 };
int firstItem = First<int>(items);
You could mod...
How to do date/time comparison
...
The following solved my problem of converting string into date
package main
import (
"fmt"
"time"
)
func main() {
value := "Thu, 05/19/11, 10:47PM"
// Writing down the way the standard time would look like formatted our way
layout := "Mon, 01/02/...
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
...
I fixed this issue by correcting my jdbc string.
For example, the correct jdbc string should be...
jdbc:oracle:thin:@myserver:1521/XE
But the jdbs string I was using is ...
jdbc:oracle:thin:@myserver:1521:XE
(Note: between 1521 and XE should be a /)
This b...
How to get multiple counts with one SQL query?
...ally the same thing as a PIVOT function in some RDBMS:
SELECT distributor_id,
count(*) AS total,
sum(case when level = 'exec' then 1 else 0 end) AS ExecCount,
sum(case when level = 'personal' then 1 else 0 end) AS PersonalCount
FROM yourtable
GROUP BY distributor_id
...
How to ignore a property in class if null, using json.net
...hing in VB and it is no longer part of the JSON. This will only work with Strings though. Properties that are enums or integers will always show up - setting to Nothing results in the default value of "0" regardless.
– Destek
Apr 10 '17 at 15:50
...
Python module os.chmod(file, 664) does not change the permission to rw-rw-r— but -w--wx----
...
If you have desired permissions saved to string then do
s = '660'
os.chmod(file_path, int(s, base=8))
share
|
improve this answer
|
follow...