sql query to find table_name and count(table_name) in a schema - sql

Question

sql query to find table_name and count(table_name) in a schema:
Example:
I get the table_name from this query:
SELECT * FROM USER_TABLES
and count(table_name) from
select count(*) from employee
select count(*) from dept
select count(*) from subjects
now i want to get the result like this:
table_name count(table_name)
Employee 100
dept 21
subjects 56

Answer 1

Try like this
select
table_name,
to_number(
extractvalue(
xmltype(
dbms_xmlgen.getxml('select count(*) c ' ||
' from '||owner||'.'||table_name))
,'/ROWSET/ROW/C')) count
from all_tables
where table_name In (
SELECT table_name from user_tables )
OR Using Join
select
a.table_name,
to_number(
extractvalue(
xmltype(
dbms_xmlgen.getxml('select count(*) c ' ||
' from '||owner||'.'||a.table_name))
,'/ROWSET/ROW/C')) count
from all_tables a JOIN user_tables u ON
a.table_name=u.table_name AND a.owner = user

Answer 2

Looks like a typical use case for a simple UNION ALL:
select
'Employee' table_name,
count(*) from employee
union all
select
'dept' table_name,
count(*) from dept
union all
select
'subjects' table_name,
count(*) from subjects
If you want to automate this, you can iterate over USER_TABLES:
declare
l_cnt pls_integer;
begin
for cur in (select table_name from user_tables order by table_name)
loop
execute immediate 'select count(*) from ' || cur.table_name into l_cnt;
dbms_output.put_line(cur.table_name || ' ' || l_cnt);
end loop;
end;
Instead of simply printing the result, you can also build a SQL statement dynamically and use that afterwards:
declare
l_sql varchar2(4000);
begin
for cur in (select table_name from user_tables order by table_name)
loop
l_sql := l_sql || ' select ' || cur.table_name || ' as table_name, count(*) as cnt from ' || cur.table_name || ' union all';
end loop;
-- remove trailing UNION ALL
l_sql := regexp_replace(l_sql, 'union all$', '');
dbms_output.put_line(l_sql);
end;