大约有 7,000 项符合查询结果（耗时：0.0203秒） [XML]
Difference between Key, Primary Key, Unique Key and Index in MySQL
...
KEY and INDEX are synonyms in MySQL. They mean the same thing. In databases you would use indexes to improve the speed of data retrieval. An index is typically created on columns used in JOIN, WHERE, and ORDER BY clauses.
Imagine you have a table called...
How do I convert from BLOB to TEXT in MySQL?
I have a whole lot of records where text has been stored in a blob in MySQL. For ease of handling I'd like to change the format in the database to TEXT... Any ideas how easily to make the change so as not to interrupt the data - I guess it will need to be encoded properly?
...
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?
...
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
...
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
...
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/...
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
...
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
...