请教一个组合查询的sql语句

select a.*,b.YfLxMoeny from CkInfo as a left join (Select x_KxPzh,IsNull(Sum(x_LxMoney),0) as YfLxMoeny from CkLxInfo group by x_KxPzh) as b on a.Pzh=b.x_KxPzh

我这样写了以后，只能查询出CkLxInfo表中有的内容，我想无论CkLxInfo表中有无内容，都能显示出Ckinfo表中的全部的内容，如果CkLxinfo表中没有对应的内容，则该列显示为0 。请问要怎么改正这句呢？

SQL code

select a.*,ISNULL(b.YfLxMoeny ,0) AS YfLxMoeny
from CkInfo as a 
left join (Select x_KxPzh,IsNull(Sum(x_LxMoney),0) as YfLxMoeny 
from CkLxInfo group by x_KxPzh) as b on a.Pzh=b.x_KxPzh

ISNULL(col,0)