Question

I have a task of copying the data from one database to another.I don’t have privileges to create DB Link.So, I have achieved this task using COPY command in shell script. But now, I need to compare the count of records between the databases. I used to do this manually. But now,I want to automate this.

As per my knowledge, Sqlplus allows me to connect to one database at a time. But I want something like

sqlplus -s un/pwd@sid <<EOF
 SELECT count(*) FROM table1 WHERE column1 = 'abc'  -- first database
 UNION ALL
 SELECT count(*) FROM table1 WHERE column1 = 'abc';  -- second database
exit
EOF

Is it possible to omit sqlplus string and add it in the query?

Thanks,
Savitha

Answer 1

You might want to use sqlplus substitution variables to store the query results:
http://docs.oracle.com/cd/B19306_01/server.102/b14357/ch5.htm#sthref1114

These variables are global to a SQL*Plus instance, so they retain their values upon connecting to another database.

Example:

SQL> variable var1 number
SQL> variable var2 number
SQL> conn a/b@ccc
Connected.
SQL> begin
  2  select 1111 into :var1 from dual;
  3  end;
  4  /

PL/SQL procedure successfully completed.

SQL> print var1

      VAR1
----------
      1111

SQL> conn a/b@ddd
Connected.
SQL> print var1

      VAR1
----------
      1111

SQL> begin
  2  select 2222 into :var2 from dual;
  3  end;
  4  /

PL/SQL procedure successfully completed.

SQL> print :var2

      VAR2
----------
      2222

SQL> 

We can also see them like this:

SQL> print :var2 :var1

      VAR2
----------
      2222


      VAR1
----------
      1111

SQL> 

And use them in PL/SQL:

SQL> set serveroutput on
SQL> declare
  2  v1 number := :var1;
  3  v2 number := :var2;
  4  begin
  5     dbms_output.put_line('The difference is: '||to_char((v2-v1)));
  6  end;
  7  /
The difference is: 1111

PL/SQL procedure successfully completed.

SQL>