大约有 47,000 项符合查询结果（耗时：0.0505秒） [XML]
How to display unique records from a has_many through relationship?
...r the SQL DISTINCT stmt (e.g. has_many :products, :through => :orders, :select => "DISTINCT products.*). In the first case, ALL records are fetched and rails removes the duplicates for you. In the later case, only non-duplicate records are fetched from the db so it might offer better performan...
SQL update trigger only when column is modified
...dDate, ModifiedUser, ModifiedHost, QtyToRepairOld, QtyToRepairNew)
SELECT S.OrderNo, S.PartNumber, GETDATE(), SUSER_NAME(), HOST_NAME(), D.QtyToRepair, I.QtyToRepair FROM SCHEDULE S
INNER JOIN Inserted I ON S.OrderNo = I.OrderNo and S.PartNumber = I.PartNumber
INNER JOIN Dele...
Is a view faster than a simple query?
...e the indexed view directly, or, more importantly, the query optimizer can select the view if it determines that the view can be substituted for some or all of the query in the lowest-cost query plan. In the second case, the indexed view is used instead of the underlying tables and their ordinary in...
PDO support for multiple queries (PDO_MYSQL, PDO_MYSQLND)
...
Then
try {
$db->query('SET NAMES gbk');
$stmt = $db->prepare('SELECT * FROM 2_1_paidused WHERE NumberRenamed = ? LIMIT 1');
$stmt->execute(array("\xbf\x27 OR 1=1 /*"));
}
catch (PDOException $e){
echo "DataBase Errorz: " .$e->getMessage() .'<br>';
}
catch (Exception $e...
How to change the default GCC compiler in Ubuntu?
... @thang also called cc: root@host:/root# update-alternatives --get-selections | grep '/usr/bin/gcc' cc auto /usr/bin/gcc
– jopasserat
Aug 13 '16 at 15:26
...
mysql create user if not exists
...
I use
SELECT EXISTS (SELECT DISTINCT user FROM mysql.user WHERE user = "username") as is_user
should return 1 if exists or 0 if it does not
share
...
The backend version is not supported to design database diagrams or tables
...se the version designed for your database version. You can use the command select @@version to check which version of sql server you are actually using. This version is reported in a way that is easier to interpret than that shown in the Help About in SSMS.
Using a newer version of SSMS than your...
Best way to store time (hh:mm) in a database
...t a glance and performing calculations on them are straightforward.
E.g.
SELECT DATEDIFF(MINUTE, event_start, event_end)
ISO8601 date standard
If using SQLite then you don't have this, so instead use a Text field and store it in ISO8601 format eg.
"2013-01-27T12:30:00+0000"
Notes:
This use...
How to move files from one git repo to another (not a clone), preserving history
...eve it will appear to have been created at the point it was moved into the selected subdirectory. If you want to select just one file, have a look at --index-filter in the filter-branch manpage.
– Cascabel
Apr 3 '12 at 16:48
...
Objective-C implicit conversion loses integer precision 'NSUInteger' (aka 'unsigned long') to 'int'
I'm working through some exercises and have got a warning that states:
4 Answers
4
...