用sql 实现报表查询

select sales.a,sales.b - inbuy.b - cost1.b - cost2.b
from
(select date as a,sum(销售额) as b from 销售表 where date between 开始日期 and 结束日期 group by date ) as sales,
(select date as a,sum(进货额) as b from 进货表 where date between 开始日期 and 结束日期 group by date) as inbuy,
(select date as a,sum(支出额) as b from 企业支出费用表 where date between 开始日期 and 结束日期 group by date) as cost1,
(select date as a,sum(费用额) as b from 其他费用表 where date between 开始日期 and 结束日期 group by date) as cost2
where
sales.a = inbuy.a and
sales.a = cost1.a and
sales.a = cost2.a

SELECT x.riqi,(x.xiaoshoue - j.chengben - z.feiyong - q.qita) AS lirun FROM xiaoshou X,jinhuo j,zhichu z,qita q WHERE x.riqi = j.riqi AND x.riqi = z.riqi AND x.riqi = q.riqi

4张表，销售表、进货表、企业支出费用表、其他费用表 是怎么关联的？用哪个字段？

没有字段怎么写