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Select first row in each GROUP BY group?
...mon problem can surprisingly be found in the one of most official sources, MySQL manual! See Examples of Common Queries :: The Rows Holding the Group-wise Maximum of a Certain Column.
PDB文件：每个开发人员都必须知道的 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...该都知道PDB文件是用来帮助软件的调试的。但是他究竟是如何工作的呢，我们可能并不熟悉。本文描述了PDB文件的存储和内容。同时还描 述了debugger如何找到binay相应的PDB文件，以及debugger如何找到与binay对应的源代码文件。本文...
XAMPP - MySQL shutdown unexpectedly
When I open XAMPP and click start MySQL button and it gives me an error.
I had started it just before, but now it isn't working.
...
Why does C++ require a user-provided default constructor to default-construct a const object?
...type X (or array thereof), X
is const-default-constructible,
if T is a union with at least one non-static data member, exactly one variant member has a default member initializer,
if T is not a union, for each anonymous union member with at least one non-static data member (if any), exactly on...
PDO MySQL: Use PDO::ATTR_EMULATE_PREPARES or not?
...
To answer your concerns:
MySQL >= 5.1.17 (or >= 5.1.21 for the PREPARE and EXECUTE statements) can use prepared statements in the query cache. So your version of MySQL+PHP can use prepared statements with the query cache. However, make careful ...
CHECK constraint in MySQL is not working
...
MySQL 8.0.16 is the first version that supports CHECK constraints.
Read https://dev.mysql.com/doc/refman/8.0/en/create-table-check-constraints.html
If you use MySQL 8.0.15 or earlier, the MySQL Reference Manual says:
T...
Difference between CTE and SubQuery?
... most useful for recursion:
WITH hier(cnt) AS (
SELECT 1
UNION ALL
SELECT cnt + 1
FROM hier
WHERE cnt < @n
)
SELECT cnt
FROM hier
will return @n rows (up to 101). Useful for calendars, dummy rowsets etc.
They are also more readable (i...
Convert json data to a html table [closed]
...s a header row to the table and returns the set of columns.
// Need to do union of keys from all records as some records may not contain
// all records.
function addAllColumnHeaders(myList, selector) {
var columnSet = [];
var headerTr$ = $('<tr/>');
for (var i = 0; i < myList....
PDOException “could not find driver”
I have just installed Debian Lenny with Apache, MySQL, and PHP and I am receiving a PDOException could not find driver .
3...
MySQL Server has gone away when importing large sql file
...
As stated here:
Two most common reasons (and fixes) for the MySQL server has gone away
(error 2006) are:
Server timed out and closed the connection. How to fix:
check that wait_timeout variable in your mysqld’s my.cnf configuration file is large enough. On Debian: su...