大约有 44,000 项符合查询结果(耗时:0.0247秒) [XML]

https://stackoverflow.com/ques... 

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...
https://stackoverflow.com/ques... 

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 ...
https://stackoverflow.com/ques... 

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: ...
https://stackoverflow.com/ques... 

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...
https://stackoverflow.com/ques... 

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...
https://stackoverflow.com/ques... 

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 '...
https://stackoverflow.com/ques... 

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...
https://stackoverflow.com/ques... 

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...
https://stackoverflow.com/ques... 

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...
https://stackoverflow.com/ques... 

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...