SQL 必知必会笔记5创建计算字段
字段（field） 基本上与列（column）的意思相同，经常互换使用，不过数据库列一 般称为列，而术语字段通常与计算字段一起使用。 拼接(concatenate) 将值联结到一起（将一个值附加到另一个值）构成单个值。 Access 和SQL Server 使用+号。DB2、Oracle、Postgr
字段（field）
基本上与列（column）的意思相同，经常互换使用，香港空间，不过数据库列一 般称为列，香港服务器，而术语字段通常与计算字段一起使用。
拼接(concatenate)
将值联结到一起（将一个值附加到另一个值）构成单个值。
Access 和SQL Server 使用+号。DB2、Oracle、PostgreSQL、SQLite 和 Open Office Base 使用||。详细请参阅具体的DBMS 文档。
vend_country Vendors ORDER BY vend_name; ，虚拟主机
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