摘要:
高级查询 1.连接查询,对结果集列的扩展select * from info select * from info,nation #形成笛卡尔积select * from info,nation where info.nation=nation.codeselect info.code,info.n 阅读全文
摘要:
简单查询 1.最简单查询(查所有数据)select * from 表名; 注:* 代表所有列select * from info 2.查询指定列select code,name from info 3.修改结果集的列名select code as '代号',name as '姓名' from inf 阅读全文