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When should I use cross apply over inner join?
What is the main purpose of using CROSS APPLY ?
13 Answers
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Objective-C: difference between id and void *
... barriers for references of type id, but not for type void *. When declaring structures, this can be a critical difference. Declaring iVars like void *_superPrivateDoNotTouch; will cause premature reaping of objects if _superPrivateDoNotTouch is actually an object. Don't do that.
attempting to ...
How to find serial number of Android device?
...a good candidate. How do I retrieve the serial number of an Android device in my app ?
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Want to find records with no associated records in Rails
...s is still pretty close to SQL, but it should get everyone with no friends in the first case:
Person.where('id NOT IN (SELECT DISTINCT(person_id) FROM friends)')
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How to use GROUP_CONCAT in a CONCAT in MySQL
If I have a table with the following data in MySQL:
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Possibility of duplicate Mongo ObjectId's being generated in two different collections?
... possible for the same exact Mongo ObjectId to be generated for a document in two different collections? I realize that it's definitely very unlikely, but is it possible?
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Migration: Cannot add foreign key constraint
I'm trying to create foreign keys in Laravel however when I migrate my table using artisan i am thrown the following error:
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MySQL INNER JOIN select only one row from second table
... user, those of which have payments, may have multiple associated payments in the payments table. I would like to select all users who have payments, but only select their latest payment. I'm trying this SQL but i've never tried nested SQL statements before so I want to know what i'm doing wrong. ...
RESTful on Play! framework
We are planning a project primarily serving content to mobile apps, but need to have a website.
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Can I use CASE statement in a JOIN condition?
The following image is a part of Microsoft SQL Server 2008 R2 System Views. From the image we can see that the relationship between sys.partitions and sys.allocation_units depends on the value of sys.allocation_units.type . So to join them together I would write something similar to this:
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