大约有 46,000 项符合查询结果（耗时：0.0400秒） [XML]
Oracle “(+)” Operator
...dize OUTER joins.
The query would be re-written in ANSI-92 syntax as:
SELECT ...
FROM a
LEFT JOIN b ON b.id = a.id
This link is pretty good at explaining the difference between JOINs.
It should also be noted that even though the (+) works, Oracle recommends not using it:
Oracle re...
Select 50 items from list at random to write to file
... leaving the original population unchanged. The resulting list is
in selection order so that all sub-slices will also be valid random
samples. This allows raffle winners (the sample) to be partitioned
into grand prize and second place winners (the subslices).
Members of the popul...
How do I find duplicates across multiple columns?
...
Duplicated id for pairs name and city:
select s.id, t.*
from [stuff] s
join (
select name, city, count(*) as qty
from [stuff]
group by name, city
having count(*) > 1
) t on s.name = t.name and s.city = t.city
...
Get day of week in SQL Server 2005/2008
...
Use DATENAME or DATEPART:
SELECT DATENAME(dw,GETDATE()) -- Friday
SELECT DATEPART(dw,GETDATE()) -- 6
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Convert INT to VARCHAR SQL
I am using Sybase and I am doing a select which returns me a column called "iftype", but its type is int and I need to convert into varchar. When I try to do the select without the convert function I get this error:
...
How to generate Class Diagram (UML) on Android Studio (IntelliJ Idea)
...ight click on the folder containing the classes you want to visualize, and select Add to simpleUML Diagram.
That's it; you have you fancy class diagram generated from your code!
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SQL selecting rows by most recent date
...eturns a result set with ChargeId, ChargeType, and MostRecentServiceMonth
SELECT
CHARGEID,
CHARGETYPE,
MAX(SERVICEMONTH) AS "MostRecentServiceMonth"
FROM INVOICE
GROUP BY CHARGEID, CHARGETYPE
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Check if table exists and if it doesn't exist, create it in SQL Server 2008
...
Something like this
IF NOT EXISTS (SELECT * FROM sys.objects
WHERE object_id = OBJECT_ID(N'[dbo].[YourTable]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[YourTable](
....
....
....
)
END
...
Reshaping data.frame from wide to long format
...
Here is another example showing the use of gather from tidyr. You can select the columns to gather either by removing them individually (as I do here), or by including the years you want explicitly.
Note that, to handle the commas (and X's added if check.names = FALSE is not set), I am also us...
Remove Select arrow on IE
I have select element, i want to remove the arrow, then i can add other icon..
i can do that for Firefox Safari and Chrome,
but this didn't work on IE9 .
...