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Difference between JOIN and INNER JOIN
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Is this true for all data bases (e.g. SQL, postgres?) Does anyone know a link to the documentation explaining this?
– Chogg
Oct 25 '17 at 17:32
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SQL JOIN - WHERE clause vs. ON clause
After reading it, this is not a duplicate of Explicit vs Implicit SQL Joins .
The answer may be related (or even the same) but the question is different.
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SQL Add foreign key to existing column
If I am using the following SQL command in SQL Server 2008 to update a table with a foreign key constraint:
6 Answers
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Why all the Active Record hate? [closed]
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end
people = Person.find(:all, :include => :company )
This generates SQL with LEFT JOIN companies on companies.id = person.company_id, and automatically generates associated Company objects so you can do people.first.company and it doesn't need to hit the database because the data is already p...
Best way to work with transactions in MS SQL Server Management Studio
Let's say I have an SQL statement that's syntactically and semantically correct so it executes.
2 Answers
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1052: Column 'id' in field list is ambiguous
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SQL supports qualifying a column by prefixing the reference with either the full table name:
SELECT tbl_names.id, tbl_section.id, name, section
FROM tbl_names
JOIN tbl_section ON tbl_section.id = tbl_names.id
...or a ta...
How to use NULL or empty string in SQL
...ow to use NULL and an empty string at the same time in a WHERE clause in SQL Server. I need to find records that have either null values or an empty string. Thanks.
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Using IQueryable with Linq
...t;= 25.00);
The code looks the same, but the difference here is that the SQL executed will be SELECT * FROM Products WHERE Cost >= 25.
From your POV as a developer, this looks the same. However, from a performance standpoint, you may only return 2 records across the network instead of 20,000....
What exactly is Arel in Rails 3.0?
...ement for ActiveRecord
No, it isn't. It's a replacement for hand-crafting SQL queries in strings. It is a common query layer that underlies ActiveRecord, but it can also be used as an underpinning for DataMapper, for example.
If it is a replacement for anything, it's a replacement for Ambition. Or,...
How to rename a table in SQL Server?
The SQL query that I have used is :
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