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Rails 3: Get Random Record
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Thing.first(:order => "RANDOM()") # For MySQL :order => "RAND()", - thanx, @DanSingerman
# Rails 3
Thing.order("RANDOM()").first
or
Thing.first(:offset => rand(Thing.count))
# Rails 3
Thing.offset(rand(Thing.count)).first
Actually, in Rails 3 all example...
Remove Primary Key in MySQL
... following table schema which maps user_customers to permissions on a live MySQL database:
12 Answers
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Generate GUID in MySQL for existing Data?
I've just imported a bunch of data to a MySQL table and I have a column "GUID" that I want to basically fill down all existing rows with new and unique random GUID's.
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how to convert a string to date in mysql?
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As was told at MySQL Using a string column with date text as a date field, you can do
SELECT STR_TO_DATE(yourdatefield, '%m/%d/%Y')
FROM yourtable
You can also handle these date strings in WHERE clauses. For example
SELECT whatever...
How to delete duplicates on a MySQL table?
I need to DELETE duplicated rows for specified sid on a MySQL table.
25 Answers
25...
App Inventor 2开发计步器与定位器 - App Inventor 2 中文网 - 清泛IT论坛，有思想、有深度
...编写“健身宝”手机应用程序
3.问题：
（1）如何获取走路步数、距离？
（2）如何计算走路时间？
（3）如何获得当前位置？
（4）如何存储信息？
4.规划：
（1）利用pedometer（计步器）组件...
MySQL Cannot Add Foreign Key Constraint
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lol same. MySQL could use more precise error handling on this kind of stuff.
– dave
Apr 17 at 23:38
add a comm...
Why is it bad style to `rescue Exception => e` in Ruby?
... You can also ADAPTER_ERRORS = [::ActiveRecord::StatementInvalid, PGError, Mysql::Error, Mysql2::Error, ::ActiveRecord::JDBCError, SQLite3::Exception] and then rescue *ADAPTER_ERRORS => e
– j_mcnally
Feb 27 '14 at 2:19
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What scalability problems have you encountered using a NoSQL data store? [closed]
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I've switched a small subproject from MySQL to CouchDB, to be able to handle the load. The result was amazing.
About 2 years ago, we've released a self written software on http://www.ubuntuusers.de/ (which is probably the biggest German Linux community website)....
Delete with Join in MySQL
...ect_id = posts.project_id AND projects.client_id = :client_id;
BTW, with mysql using joins is almost always a way faster than subqueries...
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