ds1的列,向下扩展,并作为参数传给ds2列进行查询,但发现这个ds2查询只会查一次,并没有跟随ds1进行向下扩展查询; ds1: SELECT '3' aa FROM dual union all SELECT '2' aa FROM dual union all SELECT '1' aa FROM dual ds2: select * from( SELECT '1' aa,'a' bb FROM dual union all SELECT '2' aa,'b' bb FROM dual union all SELECT '3' aa,'c' bb FROM dual ) where aa = '${a}' 内容为 这就是ds2只执行了第一行的传的参数3 |