select case when a.cnt = b.cnt then '两个库结构一致'

when a.cnt <> b.cnt then '两个库结构不一致' end

from (select count(*) as cnt

from dba_tab_columns t1, dba_tab_columns@lnk_db2 t2

where t1.owner = 'TAOBAO'

and t1.owner = t2.owner

and t1.table_name = t2.table_name

and t1.column_name = t2.column_name

and t1.data_type = t2.data_type

and t1.data_length = t2.data_length

and t1.nullable = t2.nullable

and nvl(t1.data_precision, 0) = nvl(t2.data_precision, 0)

and nvl(t1.data_scale, 0) = nvl(t2.data_scale, 0)) a,

(select count(*) as cnt

from dba_tab_columns

where owner = 'TAOBAO') b