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What can you use Python generator functions for?
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Real World Example
Let's say you have 100 million domains in your MySQL table, and you would like to update Alexa rank for each domain.
First thing you need is to select your domain names from the database.
Let's say your table name is domains and column name is domain.
If you use SELECT...
Select all columns except one in MySQL?
... trying to use a select statement to get all of the columns from a certain MySQL table except one. Is there a simple way to do this?
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How to add not null constraint to existing column in MySQL
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Oddly I was getting an error (MySQL 5.6, Workbench 6.3) changing/modifying a column I'd named null_heart_rate_count, error was #1138, Invalid use of NULL value. I had to drop and add the column instead.
– William T. Mallard
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领域驱动设计系列（五）:事件驱动之异步事件 - 更多技术 - 清泛网 - 专注C/...
...以。
另外，异步要处理的东西很多，比如处理完毕后，如何通知用户，还是让用户刷新？ 我个人建议，一般情况下都不要用异步，只有在真的需要的时候再用。
作者: 王德水
出处：http://deshui.wang
领域驱动设计 DDD 事件驱...
How do write IF ELSE statement in a MySQL query
How do I write an IF ELSE statement in a MySQL query?
5 Answers
5
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MySQL: ignore errors when importing?
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Use the --force (-f) flag on your mysql import. Rather than stopping on the offending statement, MySQL will continue and just log the errors to the console.
For example:
mysql -u userName -p -f -D dbName < script.sql
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TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes
Per the MySQL docs , there are four TEXT types:
4 Answers
4
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Node.js app can't run on port 80 even though there's no other process blocking the port
... applications on that port. On Linux systems, any port below 1024 requires root access.
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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...
When and why are database joins expensive?
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MySQL, Oracle, SQL Server, Sybase, postgreSQL,etc. care not the order of joins. I've worked with DB2 and it also, to my knowledge, doesn't care what order you put them in. This is not helpful advice in the general case
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