大约有 44,000 项符合查询结果（耗时：0.0231秒） [XML]
How can I split and trim a string into parts all on one line?
...
Try
List<string> parts = line.Split(';').Select(p => p.Trim()).ToList();
FYI, the Foreach method takes an Action (takes T and returns void) for parameter, and your lambda return a string as string.Trim return a string
Foreach extension method is meant to modif...
Why does String.valueOf(null) throw a NullPointerException?
...s
How does polymorph ambiguity distinction work?
Which overload will get selected for null in Java?
Moral of the story
There are several important ones:
Effective Java 2nd Edition, Item 41: Use overloading judiciously
Just because you can overload, doesn't mean you should every time
They ...
How to extract year and month from date in PostgreSQL without using to_char() function?
I want to select sql:
SELECT "year-month" from table group by "year-month" AND order by date , where
year-month - format for date "1978-01","1923-12".
select to_char of couse work , but not "right" order:
...
Delete duplicate records in SQL Server?
...r the dupes by empId, and delete all but the first one.
delete x from (
select *, rn=row_number() over (partition by EmployeeName order by empId)
from Employee
) x
where rn > 1;
Run it as a select to see what would be deleted:
select *
from (
select *, rn=row_number() over (partition b...
Oracle Differences between NVL and Coalesce
...the first non-NULL (there are some exceptions, such as sequence NEXTVAL):
SELECT SUM(val)
FROM (
SELECT NVL(1, LENGTH(RAWTOHEX(SYS_GUID()))) AS val
FROM dual
CONNECT BY
level <= 10000
)
This runs for almost 0.5 seconds, since it generates...
How long is the SHA256 hash?
...
you can use this select statement to test it: SELECT length(to_base64(unhex(sha2('say hello to my little friend',256)))) , it is always 44 whatever the length of original string is.
– DrAhmedJava
Apr 9 '...
Group query results by month and year in postgresql
...
select to_char(date,'Mon') as mon,
extract(year from date) as yyyy,
sum("Sales") as "Sales"
from yourtable
group by 1,2
At the request of Radu, I will explain that query:
to_char(date,'Mon') as mon, : convert...
Rank function in MySQL
...
One option is to use a ranking variable, such as the following:
SELECT first_name,
age,
gender,
@curRank := @curRank + 1 AS rank
FROM person p, (SELECT @curRank := 0) r
ORDER BY age;
The (SELECT @curRank := 0) part allows the variable initializatio...
How do I view the full content of a text or varchar(MAX) column in SQL Server 2008 Management Studio
...ta.
DECLARE @S varchar(max) = 'A'
SET @S = REPLICATE(@S,100000) + 'B'
SELECT @S as [XML_F52E2B61-18A1-11d1-B105-00805F49916B]
In SSMS (at least versions 2012 to current of 18.3) this displays the results as below
Clicking on it opens the full results in the XML viewer. Scrolling to the rig...
How to calculate age (in years) based on Date of Birth and getDate()
...low:
try this:
DECLARE @dob datetime
SET @dob='1992-01-09 00:00:00'
SELECT DATEDIFF(hour,@dob,GETDATE())/8766.0 AS AgeYearsDecimal
,CONVERT(int,ROUND(DATEDIFF(hour,@dob,GETDATE())/8766.0,0)) AS AgeYearsIntRound
,DATEDIFF(hour,@dob,GETDATE())/8766 AS AgeYearsIntTrunc
OUTPUT:
Age...