sql 两个表联合查询

[xyq0125]

select a.Id,a.RName,c.Formula,c.Mscore,c.Wscore,c.Number from Rules as a,JLScore as c 
where a.Flag='1' and a.Rid='1' and c.Jid='2' and c.JType =a.Id

select Id,RName from Rules where Rid='1'

上面两条sql查询得到的结果为：
id RName Formula Mscore Wscore Number
1 细则1 (完成值-目标值)*基数 200 210 3

Id RName
1 细则1
2 细则2

问：我要如何写sql语句能将两个接口合并？
效果：
Id RName Formula Mscore Wscore Number
1 细则1 (完成值-目标值)*基数 200 210 3
2 细则2 null null null null

[xyq0125]

1楼解决问题。
2楼方法报错啊。
3楼接口不是我想要的。

[油泼白菜]

LEFT JOIN 返回左表中所有的行

[风2013]

用 left join 链接两条语句的结果集

select c.* ,b.*  from  (select Id,RName from Rules where Rid='1') c
left join

(select a.Id,a.RName,c.Formula,c.Mscore,c.Wscore,c.Number from Rules as a,JLScore as c 
where a.Flag='1' and a.Rid='1' and c.Jid='2' and c.JType =a.Id) d on c.id=d.id

[yesterday5100]

select a.Id,a.RName,c.Formula,c.Mscore,c.Wscore,c.Number from Rules as a,JLScore as c
where a.Flag='1' and a.Rid='1' and c.Jid='2' and c.JType =a.Id
union
select Id,RName from Rules where Rid='1'

[JayPan2008]

SELECT a.Id,a.RName,c.Formula,c.Mscore,c.Wscore,c.Number FROM @Rules AS a
LEFT JOIN @JLScore as c
ON c.JType =a.Id AND a.Flag='1' and a.Rid='1' and c.Jid='2'