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How to filter SQL results in a has-many-through relation
... skin a cat?
The precise cat-skinning environment for this test:
PostgreSQL 9.0 on Debian Squeeze with decent RAM and settings.
6.000 students, 24.000 club memberships (data copied from a similar database with real life data.)
Slight diversion from the naming schema in the question: student.id is...
How to create a unique index on a NULL column?
I am using SQL Server 2005. I want to constrain the values in a column to be unique, while allowing NULLS.
4 Answers
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LEFT OUTER JOIN in LINQ
...roups.Name
}
);
var xy = (query2).ToList();
When used with LINQ 2 SQL it will translate nicely to the following very legible SQL query:
SELECT
users.USR_ID AS UserId
,users.USR_User AS UserName
,groups.ID AS UserGroupId
,groups.Name AS GroupName
FROM T_User AS users
...
How can I join multiple SQL tables using the IDs?
...%3a%2f%2fstackoverflow.com%2fquestions%2f9853586%2fhow-can-i-join-multiple-sql-tables-using-the-ids%23new-answer', 'question_page');
}
);
Post as a guest
Na...
What's wrong with nullable columns in composite primary keys?
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In Sql Server a unique constraint that has a nullable column, allows the value 'null' in that column only once (given identical values for the other columns of the constraint). So such a unique constraint essentially behaves lik...
BACKUP LOG cannot be performed because there is no current database backup
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Please see below image and apply changes in SqlServer :
first right click on Database --> Task --> Restore --> Select Backup File -->
Finally Apply Change in Options Tab.
share
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How do I set a column value to NULL in SQL Server Management Studio?
...rtcut is specific to SSMS (and its predecessor, Enterprise Manager). Azure SQL Server features are all built in an entirely new interface on the web.
– TylerH
2 days ago
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Extracting hours from a DateTime (SQL Server 2005)
...omoting lazy shorthand that leads to confusion or worse. See #6 here blogs.sqlsentry.com/aaronbertrand/… and sqlblog.com/blogs/aaron_bertrand/archive/2011/09/20/…
– Aaron Bertrand
Oct 6 '14 at 19:44
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What is the equivalent of bigint in C#?
...t am I supposed to use when handling a value in C#, which is bigint for an SQL Server database?
10 Answers
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SQL Group By with an Order By
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In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:
SELECT COUNT(id) AS theCount, `Tag` from `images-tags`
GROUP BY `Tag`
ORDER BY theCount DESC
LIMIT 20
...