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how do I query sql for a latest record date for each user
I have a table that is a collection entries as to when a user was logged on.
22 Answers
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selecting unique values from a column
I have a MySQL table which contains the following type of information:
9 Answers
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MySQL主从服务器数据一致性的核对与修复 - 数据库(内核) - 清泛网 - 专注C/...
...一天被掩盖的问题会再次爆发出来。
Percona Toolkit里的pt-table-checksum和pt-table-sync可以搞定此类问题。它们的安装很简单，可以依照自己的操作系统选择下载rpm或者deb软件包来安装，当然也可以使用源代码来安装，不过要注意的是...
Explaining difference between automaticallyAdjustsScrollViewInsets, extendedLayoutIncludesOpaqueBars
...his property is used when your view is a UIScrollView or similar, like a UITableView. You want your table to start where the navigation bar ends, because you wont see the whole content if not, but at the same time you want your table to cover the whole screen when scrolling. In that case, setting ed...
How to get last inserted row ID from WordPress database?
My WordPress plugin has a table with a AUTO_INCREMENT primary key field called ID. When a new row is inserted into the table, I'd like to get the ID value of the insertion.
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SELECT * WHERE NOT EXISTS
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You didn't join the table in your query.
Your original query will always return nothing unless there are no records at all in eotm_dyn, in which case it will return everything.
Assuming these tables should be joined on employeeID, use the foll...
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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Joins are for lazy people?
...d that using joins is less efficient than making several requests and link tables in the code (C# or Java).
21 Answers
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What is PAGEIOLATCH_SH wait type in SQL Server?
...stem.
In practice, this almost always happens due to large scans over big tables. It almost never happens in queries that use indexes efficiently.
If your query is like this:
Select * from <table> where <col1> = <value> order by <PrimaryKey>
, check that you have a composit...
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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