1、mysql MySQL 中 null 不代表任务实际的值,类似于一个未知数。 2.执行对比 2.1 查询条件为 =null 执行之后,发现返回行数为0 2.2 查询条件为 is null 执行后发现返回行数为8 2.3两次查询的为何不同 null 在MySQL中不代表任何值,通过运算符是得不到任何结果的,因此只能用 is null(默认情况) 3、oracle 在...
MySQL is officially pronounced “My ess-cue-el,” but “my sequel” is a common variation. As the name suggests, MySQL is a SQL-based relational database designed to store and manage structured data. In recent years, however, Oracle added additional support, including for the popular JSON ...
[mysqld] innodb_directories="directory_path_1;directory_path_2" The following procedure is applicable to moving individual file-per-table and general tablespace files, system tablespace files, undo tablespace files, or the data directory. Before moving files or directories, review the usage notes ...
支持 深入的类型映射,比如pgsql的数组类型; 支持 丰富的表达式函数,以及灵活的自定义解析; 支持 导航属性一对多、多对多贪婪加载,以及延时加载; 支持 读写分离、分表分库,租户设计,过滤器,乐观锁,悲观锁; 支持MySql/SqlServer/PostgreSQL/Oracle/Sqlite/达梦数据库/Access; ...
temptable_use_mmap (Deprecated in MySQL 8.0.26) OFF ONClone plugin. The clone plugin versioning requirement was relaxed to allow cloning between different point releases in the same series. In other words, only the major and minor version numbers must match when previously the point release num...
line 353, in call_analyze if not self.active_module.analyze_file(): File "/Applications/MySQLWorkbench.app/Contents/Resources/plugins/sqlide_power_import_export_be.py", line 537, in analyze_file self.has_header = csv.Sniffer().has_header(csvsample) File "/System/Library/Frameworks/Python....
Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type '\help' or '\?' for help; '\quit' to exit. Creating a session to 'dba@tidb60:3366' Fetching schema names for autocompletion... Press ^C to stop...
Category:MySQL Server: DMLSeverity:S3 (Non-critical) Version:5.1.58, 5.5.20OS:Any Assigned to:CPU Architecture:Any Tags:collation,like,SQL,Unicode,utf8 [21 Dec 2011 19:34] Kevin Qiu Description:A SQL statement with LIKE %<pattern>%, will return rows containing <pattern>, however, when ...
I'm maintaining a MySql driven inventory application. There are two tables, items and buyers. When the system was designed, it was decided that two columns would be used to uniquely identify rows in the items table, SKU and owner_id. Any purchases made for an item in the items table wou...
and who is developing MariaDB. MariaDB is developed by many of the original developers of MySQL who now work for MariadB foundation and SkySQL Ab, and by many people in the community. MySQL, which is the base of MariaDB, is a product and trademark of Oracle Corporation, Inc. For a li...