Query to find all empty tables - oracle

Question

Considering that I have a Schema named SBST
I want to find all empty tables list in this SBST Schema. Is there any PL/SQL procedure to find that. I found few. But those were using user tables where I was not able specify the Schema name SBST.
I was using this
select table_name from dba_tables where owner ='SBST'
having count(*)=0 group by table_name
What's wrong in the above query?

Answer 1

You can fire below query to find the list of tables haveing no data
select * from ALL_TABLES
where owner ='SBST'
AND NUM_ROWS = 0;

Answer 2

Similar to #shareef's answer, but using dynamic SQL to avoid having to create the temporary .sql file. You'll need dbms_output to be visible, e.g. with set serveroutput on in SQL*Plus - don't know about Toad.
declare
cursor c(p_schema varchar2) is
select 'select ''' || table_name || ''' from ' ||
p_schema ||'.' || table_name || ' where rownum < 2 ' ||
' having count(*) = 0' as query
from all_tables
where owner = p_schema
order by table_name;
l_table all_tables.table_name%TYPE;
begin
for r in c('SBST') loop
begin
execute immediate r.query into l_table;
exception
when no_data_found then continue;
end;
dbms_output.put_line(l_table);
end loop;
end;
/
Using all_tables seems more useful than dba_tables here so you know you can select from the tables it lists. I've also included the schema in the from clause in case there other users have tables with the same name, and so you can still see it if you're connected as a different user - possibly avoiding synonym issues too.
Specifically what's wrong with your query... you've got the having and group by clauses the wrong way around; but it will always return no data anyway because if SBST has any tables then count (*) from dba_tables must be non-zero, so the having always matches; and if it doesn't then, well, there's no data anyway so there's nothing for the having to match against. You're counting how many tables there are, not how many rows are in each table.

Answer 3

the straight forward answer is
select 'select ''' || table_name || ''' from ' || table_name || '
having count(*) = 0;' from dba_tables where owner='SBST';
EXPLANATION
You can run this... it will just output the table names of those having no rows:
assuming you use sqlplus but i used toad to test it
and it worked very well
set echo off heading off feedback off lines 100 pages 0;
spool tmp.sql
select 'select ''' || table_name || ''' from ' || table_name || '
having count(*) = 0;' from user_tables where owner='SBST';
spool off;
#tmp.sql
If you open the "tmp.sql" file, you'll see for all tables....
select 'PERSONS' from PERSONS having count(*) = 0;
select 'DEPARTMENT' from DEPARTMENT having count(*)=0;
in your case you want a schema and schema is a user right the above code if you connect with the user SBST but if you connect with other then you have to use DBA_TABLES and assign owner attribute to SBST
USER_TABLES is tables which you own ALL_TABLES is tables which own,
and tables owner by other users, which you have been granted excplicit
access to DBA_TABLES is all tables in the database
like this
set echo off heading off feedback off lines 100 pages 0;
spool tmp.sql
select 'select ''' || table_name || ''' from ' || table_name || '
having count(*) = 0;' from dba_tables where owner='SBST';
spool off;
#tmp.sql
All three are views of the underlying SYS tables, but the USER_ and
ALL_ views joing in your username/security info to limit the results
**SUMMARY **
PLEASE JUST RUN THIS QUERY
select 'select ''' || table_name || ''' from ' || table_name || '
having count(*) = 0;' from dba_tables where owner='SBST';

Answer 4

If table stats are up to date then you could use:
SELECT TABLE_NAME
FROM ALL_TAB_STATISTICS
WHERE (OWNER = 'ME')
AND (NUM_ROWS = 0);