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How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'
...now() - INTERVAL 900 SECOND
To
DELETE FROM onlineusers
WHERE id IN (
SELECT id FROM onlineusers
WHERE datetime <= now() - INTERVAL 900 SECOND
ORDER BY id
) u;
Another thing to keep in mind is that mysql documentation suggest that in case of a deadlock the client should retry autom...
How to get the index of an item in a list in a single step?
...g different (e.g. on top of any IEnumerable<>).
Use the overload of Select which takes an index in the predicate, so you transform your list into an (index, value) pair:
var pair = myList.Select((Value, Index) => new { Value, Index })
.Single(p => p.Value.Prop == oProp...
How do I create a category in Xcode 6 or higher?
...ey just moved it without telling anyone.
Click File -> New -> File
Select Objective-C file under Sources in iOS or Mac OS respectively and Click Next
Now under File Type: choose either Category, Protocol, or Extension
PS. Under File Name: whatever you type here will be either the Category,...
Paste multiple times
...
Clever. 'p' to paste, 'gv' to re-select what was originally selected. 'y' to copy it again.
– Amjith
Aug 23 '11 at 21:17
...
sqlite database default time value 'now'
...ime('%s','now'))
);
insert into example(data) values
('foo')
,('bar')
;
select
id
,data
,created_at as epoch
,datetime(created_at, 'unixepoch') as utc
,datetime(created_at, 'unixepoch', 'localtime') as localtime
from example
order by id
;
id|data|epoch |utc |localtime
1 |foo ...
Dependency graph of Visual Studio projects
.../2003" }
$projectFiles | ForEach-Object {
$projectFile = $_ | Select-Object -ExpandProperty FullName
$projectName = $_ | Select-Object -ExpandProperty BaseName
$projectXml = [xml](Get-Content $projectFile)
$projectReferences = $projectXml | Select-Xml '//default...
MySQL Insert into multiple tables? (Database normalization?)
... 2 and 3:
Will stock the LAST_INSERT_ID() in
a MySQL variable:
INSERT ...
SELECT LAST_INSERT_ID() INTO @mysql_variable_here;
INSERT INTO table2 (@mysql_variable_here, ...);
INSERT INTO table3 (@mysql_variable_here, ...);
Will stock the LAST_INSERT_ID() in a
php variable (or any language that
can c...
How to get a group of toggle buttons to act like radio buttons in WPF?
...ike toggle buttons, but also as radio buttons where only one button can be selected / pressed down at a current time. It also need to have a state where none of the buttons are selected / pressed down.
...
Is having an 'OR' in an INNER JOIN condition a bad idea?
... a MERGE JOIN.
It can be expressed as a concatenation of two resultsets:
SELECT *
FROM maintable m
JOIN othertable o
ON o.parentId = m.id
UNION
SELECT *
FROM maintable m
JOIN othertable o
ON o.id = m.parentId
, each of them being an equijoin, however, SQL Server's optimiz...
Show constraints on tables command
...
Simply query the INFORMATION_SCHEMA:
USE INFORMATION_SCHEMA;
SELECT TABLE_NAME,
COLUMN_NAME,
CONSTRAINT_NAME,
REFERENCED_TABLE_NAME,
REFERENCED_COLUMN_NAME
FROM KEY_COLUMN_USAGE
WHERE TABLE_SCHEMA = "<your_database_name>"
AND TABLE_NAME = "<y...