大约有 7,000 项符合查询结果（耗时：0.0156秒） [XML]
How to add not null constraint to existing column in MySQL
...
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
...
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/...
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
...
MySQL: ignore errors when importing?
...
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
...
When and why are database joins expensive?
...
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
...
TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes
Per the MySQL docs , there are four TEXT types:
4 Answers
4
...
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
...
Rails 3: Get Random Record
...
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
...
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.
...