大约有 45,000 项符合查询结果（耗时：0.0400秒） [XML]
How do you write multiline strings in Go?
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@KyleHeuton: Presumably Daniele D is using the backtick character in his/her SQL queries (as MySQL users often do), and finds it painful to have to represent it as ` + "`" + ` and break copy-and-pastability.
– ruakh
Nov 29 '18 at 21:55
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Insert, on duplicate update in PostgreSQL?
...try the UPDATE again
END;
END LOOP;
END;
$$
LANGUAGE plpgsql;
SELECT merge_db(1, 'david');
SELECT merge_db(1, 'dennis');
There's possibly an example of how to do this in bulk, using CTEs in 9.1 and above, in the hackers mailing list:
WITH foos AS (SELECT (UNNEST(%foo[])).*)
updated...
How can I select an element with multiple classes in jQuery?
I want to select all the elements that have the two classes a and b .
13 Answers
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Check if a row exists, otherwise insert
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I assume a single row for each flight? If so:
IF EXISTS (SELECT * FROM Bookings WHERE FLightID = @Id)
BEGIN
--UPDATE HERE
END
ELSE
BEGIN
-- INSERT HERE
END
I assume what I said, as your way of doing things can overbook a flight, as it will insert a new row when there are 1...
How to use count and group by at the same select statement
I have an sql select query that has a group by.
I want to count all the records after the group by statement.
Is there a way for this directly from sql?
For example, having a table with users I want to select the different towns and the total number of users
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Get list of databases from SQL Server
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Execute:
SELECT name FROM master.sys.databases
This the preferred approach now, rather than dbo.sysdatabases, which has been deprecated for some time.
Execute this query:
SELECT name FROM master.dbo.sysdatabases
or if you pref...
Linq to Entities join vs groupjoin
...Join syntax would be
from p in Parent
join c in Child on p.Id equals c.Id
select new { p.Value, c.ChildValue }
returning an IEnumerable<X> where X is an anonymous type with two properties, Value and ChildValue. This query syntax uses the Join method under the hood.
GroupJoin syntax would be
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Inspecting standard container (std::map) contents with gdb
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These look to be the business!
– Richard Corden
Jan 9 '09 at 14:42
They're actually the same macros ...
How to check type of variable in Java?
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System.out.println(x + " is an double");
}
void printType(char x) {
System.out.println(x + " is an char");
}
}
then:
Typetester t = new Typetester();
t.printType( yourVariable );
share
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Spring JPA selecting specific columns
...Spring JPA to perform all database operations. However I don't know how to select specific columns from a table in Spring JPA?
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