select sj_id from tb_subject where sj_name='文史'select count(*) num from tb_content where sj_id = '25695'这2个sql语句.我要合成一个.select count(*) num from tb_content where sj_id =(select sj_id from tb_subject where sj_name='文史')这样老报一个无效数字.于是我又写成这样.select count(*) num from tb_content where sj_id =''(select sj_id from tb_subject where sj_name='文史')''但是也不对,请问遇到这样问题怎么办啊?我刚开始接触oracle,有些写法确实不知道.请指教.
不知道tb_content中的sj_id的类型与tb_subject中的sj_id类型是否相同
dlxu(脱离纯粹Coding阶段) ( ) 信誉:100 Blog 加为好友 2007-6-26 9:05:31 得分: 0
估计类型应该相同,有可能第一个查询中会查询到复数件数的数据出来吧