请教一个存储过程,读取数据表内容,并组合成查讯语句

[coolfree]

有4个表,例如 a1,a2,a3,a4,都只有一个字段n,
如何建立一个存储过程,依次打开表a1,a2,a3,a4 将每个表得字段n中得内容依次读出来,组合成一个查讯语句,这个查讯语句会很长

[coolfree]

援手啊

[benxie]

select * from a1 union
select * from a2 union
select * from a3 union
select * from a4

[txlicenhe]

Select n from a1
union all
select n from a2
union all
select n from a3
union all
select n from a4

[pengdali]

select * from (
select * from 表1
union all
select * from 表2
union all
select * from 表3
union all
select * from 表4
) tem wehre n>56

[coolfree]

大力,是要先读a1表,n字段得内容依次用 or 连接起来,放入变量z1中,然后再读a2表,把里面得n字段得内容依次读出来,用or 连接起来放入z2中,然后把z1,z2 用 and 连接