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How can a LEFT OUTER JOIN return more records than exist in the left table?
I have a very basic LEFT OUTER JOIN to return all results from the left table and some additional information from a much bigger table. The left table contains 4935 records yet when I LEFT OUTER JOIN it to an additional table the record count is significantly larger.
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Performance difference for control structures 'for' and 'foreach' in C#
...t will depend on whether you're doing any real work in the loop. In almost all cases, the difference to performance won't be significant, but the difference to readability favours the foreach loop.
I'd personally use LINQ to avoid the "if" too:
foreach (var item in list.Where(condition))
{
}
EDI...
How can I mock requests and the response?
...thons mock package to mock Pythons requests module. What are the basic calls to get me working in below scenario?
9 Answ...
What does “dereferencing” a pointer mean?
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Reviewing the basic terminology
It's usually good enough - unless you're programming assembly - to envisage a pointer containing a numeric memory address, with 1 referring to the second byte in the process's memory, 2 the third, 3 the fourth and so on....
What ha...
What optimizations can GHC be expected to perform reliably?
...has a lot of optimizations that it can perform, but I don't know what they all are, nor how likely they are to be performed and under what circumstances.
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Nested defaultdict of defaultdict
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For an arbitrary number of levels:
def rec_dd():
return defaultdict(rec_dd)
>>> x = rec_dd()
>>> x['a']['b']['c']['d']
defaultdict(<function rec_dd at 0x7f0dcef81500>, {})
>>> print json.dumps(x)
{"a": {"b": {"c": {"d": {}}}}}
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SQL Server - copy stored procedures from one db to another
...you tick the top-level checkbox beside "Stored Procedures" it selects them all together - 1 click.
– Barry Kaye
May 22 '12 at 14:06
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show 4...
How do I compare two hashes?
...=> [["c", 3]]
Hash[*difference.flatten]
=> {"c"=>3}
Doing it all in one operation and getting rid of the difference variable:
Hash[*(
(hash3.size > hash1.size) \
? hash3.to_a - hash1.to_a \
: hash1.to_a - hash3.to_a
).flatten]
=> {"c"=>3}
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Get the latest record from mongodb collection
...1 means order opposite of the one that records are inserted in.
Edit: For all the downvoters, above is a Mongoose syntax,
mongo CLI syntax is: db.collectionName.find({}).sort({$natural:-1}).limit(1)
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Which SQL query is faster? Filter on Join criteria or Where clause?
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Performance-wise, they are the same (and produce the same plans)
Logically, you should make the operation that still has sense if you replace INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = ...