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What is the difference between UNION and UNION ALL?
...cted columns need to be of the same data type.
Example: If we have two tables, 1) Employee and 2) Customer
Employee table data:
Customer table data:
UNION Example (It removes all duplicate records):
UNION ALL Example (It just concatenate records, not eliminate duplicates, so it...
Max parallel http connections in a browser?
...
A similar table can be found at http://sgdev-blog.blogspot.com/2014/01/maximum-concurrent-connection-to-same.html
– Jo.
Aug 26 '15 at 17:21
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How to change column datatype from character to numeric in PostgreSQL 8.4
...rom old to new type.
So this might work (depending on your data):
alter table presales alter column code type numeric(10,0) using code::numeric;
-- Or if you prefer standard casting...
alter table presales alter column code type numeric(10,0) using cast(code as numeric);
This will fail if you h...
How to save a data.frame in R?
...ta.Rda")
Then load it with:
load("data.Rda")
You could also use write.table() or something like that to save the table in plain text, or dput() to obtain R code to reproduce the table.
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Difference between FOR and AFTER triggers?
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There is no difference, they do the same thing.
CREATE TRIGGER trgTable on dbo.Table FOR INSERT,UPDATE,DELETE
Is the same as
CREATE TRIGGER trgTable on dbo.Table AFTER INSERT,UPDATE,DELETE
An INSTEAD OF trigger is different, and fires before and instead of the insert and can be used on...
How do I limit the number of rows returned by an Oracle query after ordering?
...).
To answer the original question, here's the query:
SELECT *
FROM sometable
ORDER BY name
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;
(For earlier Oracle versions, please refer to other answers in this question)
Examples:
Following examples were quoted from linked page, in the hope of preventing ...
MySQL Insert Where query
...TO Users(weight, desiredWeight)
SELECT weight, desiredWeight
FROM AnotherTable
WHERE id = 1
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Check for column name in a SqlDataReader object
...elp anyone setting their debugger to break on exceptions thrown.
GetSchemaTable() is also another suggestion in many answers. This would not be a preffered way of checking for a field's existance as it is not implemented in all versions (it's abstract and throws NotSupportedException in some versio...
HashSet versus Dictionary w.r.t searching time to find if an item exists
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I assume you mean Dictionary<TKey, TValue> in the second case? HashTable is a non-generic class.
You should choose the right collection for the job based on your actual requirements. Do you actually want to map each key to a value? If so, use Dictionary<,>. If you only care about it a...
What is a columnar database?
...are build upon traditional, row-oriented, DBMS, simply storing the info in tables with one (or rather often two) columns (and adding the necessary layer to access the columnar data in an easy fashion).
How do they differ from relational databases?
They generally differ from traditional (row-oriente...