Question

sql语句中的and 和or能有多个吗？另外如果语句sql语句中只能有一个and的话那当有多个条件限制时怎么办？

sql="select top 16 * from tb_goods where id not in (select top "+(nowPage*16)+" id from tb_goods where classes='"+classes2+"' and price<=500 order by id asc)and classes='"+classes2+"',price<=500";
sql="select top 16 * from tb_goods where id not in (select top "+(nowPage*16)+" id from tb_goods where classes='"+classes2+"' and price<=500 order by id asc)and classes='"+classes2+"',price<=500";这条语句对吗？

Answer 1

楼主写的是分页算法。
and classes='"+classes2+"',price<=500 这样是不对的，将逗号改成 and
另外，外面的select没有加order by ，可能分页结果不准确。
SQL中可以以多个AND或OR，当条件混乱时，可以使用括号。
如a and (b or c)这样的。
楼主补充的语句可以修改为
sql="select top 16 * from tb_goods where id not in (select top "+(nowPage*16)+" id from tb_goods where classes='"+classes2+"' and price<=500 order by id asc)and classes='"+classes2+"' and price<=500 order by id asc";

Answer 2

我晕，你最好是到秋窗那里询问，那边都是高手培训基地。没看清是数据库sql语句