How to get a rowcount from two different schema in two different databases?

Question

Hello,
I want to count of rows in each table in a schema say test, of DEV1 database to another schema say test of DEV2 database. both have same schema data in both the databases. my output should look something like this.
Tablename
database name DEV!, schema name test , tablename: count
database name DEV2, schema name test , tablename: count
can someone help me please.
Thanks a lot

Answer 1

Give this a try in dba1 - assuming there is a db link in dba1 to dba2:
select 'DBA1', count(*) from table
union all
select 'DBA2', count(*) from table@dba2
Note that if these are large tables, you may want to gather stats on the two tables (IMPORTANT) and then do
select 'DBA1', num_rows from all_tables where table_name = 'TABLE'
union all
select 'DBA2', num_rows from all_tables@dba2 where table_name = 'TABLE'
If you don't gather stats - the num_rows column in all_tables will reflect the number of rows that were present when stats were last gathered and will not reflect any inserts/deletes that have taken place since.
The "union all" clause differs from "union" in that "union all" shows every matching result from both halves of the union - whereas union will only show each unique result once.
Hope this helps!