大约有 40,000 项符合查询结果（耗时：0.0456秒） [XML]
HashSet vs. List performance
...lly a collection in the .NET framework that switches between a list and hastable implementation depending on the number of items it contains: HybridDictionary.
– MgSam
Nov 1 '13 at 2:12
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How to get distinct values for non-key column fields in Laravel?
...should use groupby. In Query Builder you can do it this way:
$users = DB::table('users')
->select('id','name', 'email')
->groupBy('name')
->get();
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Undo scaffolding in Rails
...e db:rollback before you destroy your scaffold. This will destroy/drop the table if there is no other migration except the scaffold's migration before it.
– Yakob Ubaidi
May 8 '14 at 11:06
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Thread context switch Vs. process context switch
...?t=46m8s (watch from the beginning to know more about Virtual Memory, page tables and TLB).
– piotrwest
Jun 24 '16 at 23:05
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What scalability problems have you encountered using a NoSQL data store? [closed]
...g 18,000 objects in a normalised structure: 90,000 rows across 8 different tables. Took 1 minute to retrieve and map them to our Java object model, that's with everything correctly indexed etc.
Storing them as key/value pairs using a lightweight text representation: 1 table, 18,000 rows, 3 seconds ...
MySQL integer field is returned as string in PHP
I have a table field in a MySQL database:
14 Answers
14
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ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
...nit.d/mysqld stop
Start MySQL in safe mode
sudo mysqld_safe --skip-grant-tables &
Log into MySQL using root
mysql -uroot
Select the MySQL database to use
use mysql;
Reset the password
-- MySQL version < 5.7
update user set password=PASSWORD("mynewpassword") where User='root';
-- MySQ...
MySQL and GROUP_CONCAT() maximum length
...T SESSION group_concat_max_len = 1000000;
select group_concat(column) from table group by column
You can do this even in sharing hosting, but when you use an other session, you need to repeat the SET SESSION command.
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How to export and import a .sql file from command line with options? [duplicate]
...an we set constraints like enable/disable foreign key check or export only table structure with mysqldump
– AZinkey
Feb 28 '15 at 2:48
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How to find the statistical mode?
... hope it's helpful. It is also what I was thinking anyways. You'll want to table() the data, sort and then pick the first name. It's hackish but should work.
names(sort(-table(x)))[1]
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