SQL联合更新（只要有关联字段就能执行更新！）

update t1 set KCLX=t2.KCLX,KSFS=t2.KSFS
from JX_PlannedCourse t1 
inner join JX_Course t2 on t1.KCDM=t2.KCDM
INNER JOIN JX_CourseType ON  t2.KCLX = JX_CourseType.KCLX
WHERE ISNULL(t1.KCLX,'')='' OR ISNULL(t1.KSFS,'')=''