select 仓库号;
from 职工;
where 工资>all(select 工资;
                from 职工;
                where 仓库号="WH1")

在vfp中，如果不用最大最小函数，只用ALL语句，可用如下语句
select 仓库号 from 职工 a where (工资<=all(select 工资 from 职工 where 仓库号 =a.仓库号)) and (工资>=all(select 工资 from 职工 where 仓库号='WH1'))