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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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PDO MySQL扩展模块 检测通不过？ - PHP - 清泛IT论坛，有思想、有深度
...hp.in中下面两行已经放开注释：
extension=pdo.so
extension=pdo_mysql.so
PDO检测仍然通不过。
终极解决方案：
php编译时加上如下参数，重新编译安装php：
--with-pdo-mysql
php编译安装完整参数请参见：http://www.tsingfun.com/html/2015/env_0826/...
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...
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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【最全】CSS响应式布局的5种实现方式 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...整代码与文件 可进入粉丝群获取 ！
三、rem 布局
1、rem 如何适配
rem 是相对于 html 根元素的字体大小的单位。
我们通过修改 html 中 font-size 的字体大小来控制 rem 的大小。
比如：
html {
font-size: 10px;
}
.box {
width: 10rem;
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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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Mysql: Select rows from a table that are not in another
... this only works as expected when none of the columns have NULL values. In MySQL NULL != NULL so every row that has a NULL value will be returned even if there is a duplicate row in the second table.
– Kyle Kochis
Apr 7 '15 at 2:49
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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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