如何从多张同类型表中查询数据

[jupiter418]

由于有一张比较大的表，无法上传到空间供应商的服务器（限制了最大只能上传4M的文件），因此只好将这张表分割成4张表。请教如何从这4张同类型表中查询数据，就象查询1张表一样。

一张表时查询语句如下：
select * from wuyan where z1="'.$f.'"'.'order by rand()'
改成四张表后，查询语句如下，但执行时出错，请教如下修改：
select * from wuyan_a,wuyan_b,wuyan_c,wuyan_d where z1="'.$f.'"'.'order by rand()'

[csliyu]

我建议你在数据库里面见一个view，把四张表合起来，这样不就方便多了嘛！！！

[阿_布]

select * from wuyan_a where z1='".$f."' order by rand()
union all
select * from wuyan_b where z1='".$f."' order by rand()
union all
select * from wuyan_c where z1='".$f."' order by rand()
union all
select * from wuyan_d where z1='".$f."' order by rand()

[荆棘谷-部落-王亚楠]

"select * from wuyan_a as a,wuyan_b as b,wuyan_c as,wuyang_d as d where a.z1 = b.z1 and b.z1 = c.z1 and c.z1 = d.z1 and d.z1 = '$f' order by rand()"

[阿_布]

修改一下：

select * from wuyan_a where z1='".$f."'
union all
select * from wuyan_b where z1='".$f."'
union all
select * from wuyan_c where z1='".$f."'
union all
select * from wuyan_d where z1='".$f."' 
order by rand();

[jupiter418]

[Quote=引用 1 楼 csliyu 的回复:]
我建议你在数据库里面见一个view，把四张表合起来，这样不就方便多了嘛！！！
[/Quote]

csliyu：如何建一个VIEW，能不能详细讲解一下？

[阿_布]

create view view_wuyan as
select * from wuyan_a where z1='".$f."'
union all
select * from wuyan_b where z1='".$f."'
union all
select * from wuyan_c where z1='".$f."'
union all
select * from wuyan_c where z1='".$f."';

select * from view_wuyan order by rand();

mysql视图要在mysql5.1版本以上才支持。