1、两种方式
1、select 字段名列表1,字段名列表2 from 表名列表,表名列表2; (笛卡尔积)
1、记录多的表的每一条记录,去匹配另一张表的所有记录
2、两张表的记录条数相同,则后表的每一条记录去匹配前表的所有的记录
t1 : name -> "A1" "A2" "A3" t2 : name -> "B1" "B2" select * from t1,t2; +------+-------+ | name | name2 | +------+-------+ | A1 | B1 | | A1 | B2 | | A2 | B1 | | A2 | B2 | | A3 | B1 | | A3 | B2 | +------+-------+
2、... where 条件;
示例:
select sheng.s_name as sheng,city.c_name as city,xian.x_name as xian from sheng,city,xian where sheng.s_id=city.cfather_id and city.c_id=xian.xfather_id;