select * from (
select ZZJGDM DM,ZZJGMC MC,SJJGDM SJ FROM T_ZZJG
WHERE ZZJGDM IN (SELECT ZZJGDM FROM FROM T_ZZJG T
CONNECT BY PRIOR SJJGDM=ZZJGDM
START WITH EXISTS (SELECT 1 FROM T_RY WHERE ZZJGDM=T.ZZJGDM))
UNION ALL
SELECT RYDM DM,RYMC MC,ZZJGDM SJ FROM T_RY
)
CONNECT BY PRIOR DM=SJ
START WITH SJ IS NULL
ORDER SIBLINGS BY DM
select ZZJGDM DM,ZZJGMC MC,SJJGDM SJ FROM T_ZZJG
WHERE ZZJGDM IN (SELECT ZZJGDM FROM FROM T_ZZJG T
CONNECT BY PRIOR SJJGDM=ZZJGDM
START WITH EXISTS (SELECT 1 FROM T_RY WHERE ZZJGDM=T.ZZJGDM))
UNION ALL
SELECT RYDM DM,RYMC MC,ZZJGDM SJ FROM T_RY
)
CONNECT BY PRIOR DM=SJ
START WITH SJ IS NULL
ORDER SIBLINGS BY DM
可以具体看一下执行计划,再确定如何优化
优化的空间应该不大了
能不能描述一下,或者举个例子