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Postgresql GROUP_CONCAT equivalent?
I have a table and I'd like to pull one row per id with field values concatenated.
7 Answers
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MySQL: Large VARCHAR vs. TEXT?
I've got a messages table in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserte...
Understanding garbage collection in .NET
...ow. The second duty is however completely invisible. It also generates a table that describes how the local variables inside the method body are used. That table has an entry for each method argument and local variable with two addresses. The address where the variable will first store an object ...
Condition within JOIN or WHERE
...in join improve performance for large amount of data with properly indexed tables.
– Shahdat
Oct 6 '16 at 15:13
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Ways to save enums in database
...g.
But if you wanted to really do that, i would create a Suits dimension table:
| Suit | SuitID | Rank | Color |
|------------|--------------|---------------|--------|
| Unknown | 4 | 0 | NULL |
| Heart | 1 | 1 | Red ...
What is the difference between bottom-up and top-down?
...ds the root.
Tabulation - You can also think of dynamic programming as a "table-filling" algorithm (though usually multidimensional, this 'table' may have non-Euclidean geometry in very rare cases*). This is like memoization but more active, and involves one additional step: You must pick, ahead of...
How to get innerHTML of DOMNode?
...se;
$dom->formatOutput = true;
$dom->load($html_string);
$domTables = $dom->getElementsByTagName("table");
// Iterate over DOMNodeList (Implements Traversable)
foreach ($domTables as $table)
{
echo DOMinnerHTML($table);
}
?>
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GROUP BY with MAX(DATE) [duplicate]
...ng to list the latest destination (MAX departure time) for each train in a table, for example :
6 Answers
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Reason for Column is invalid in the select list because it is not contained in either an aggregate f
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Suppose I have the following table T:
a b
--------
1 abc
1 def
1 ghi
2 jkl
2 mno
2 pqr
And I do the following query:
SELECT a, b
FROM T
GROUP BY a
The output should have two rows, one row where a=1 and a second row where a=2.
But wha...
Inserting multiple rows in a single SQL query? [duplicate]
I have multiple set of data to insert at once, say 4 rows. My table has three columns: Person , Id and Office .
4 Answe...