db中的postgres计数表

Question

I want to get the count of tables inside the 'hgp17290_data' db in pgadmin. I've been messing about with POSTGRES SQL and I can get the size of a db, like so:

select pg_database_size('hgp17290_data');

but I cant get the number of tables in this db, the below examples I couldnt get going

SELECT
    pg_database.datname,
    pg_size_pretty(pg_database_size(pg_database.datname)) AS size
    FROM pg_database;

SELECT pg_size_pretty( pg_total_relation_size('DemoLayer1'));

select count(*)
from information_schema.tables
where table_schema = 'hgp17290_data';

select * from  pg_stat_user_tables ;
select count(*) from  'GeoAppBuilderData' ; 
select * from  pg_stat_all_tables ;

SELECT count(*) FROM GeoAppBuilderData.tables WHERE table_schema NOT IN ('GeoAppBuilderData', 'pg_catalog');

select pg_database_count('hgp17290_data');

select count(1) from ('hgp17290_data');

select 'hgp17290_data' db, 'users' 'hgp17290_data', count[1] "rowscount" from hgp17290_data.users



select table_schema, 
       table_name, 
       (xpath('/row/cnt/text()', xml_count))[1]::text::int as row_count
from (
  select table_name, table_schema, 
         query_to_xml(format('select count(*) as cnt from %I.%I', table_schema, table_name), false, true, '') as xml_count
  from information_schema.tables
  where table_schema = 'hgp17290_data' --<< change here for the schema you want

  SELECT COUNT(*) FROM ('hgp17290_data');

  SELECT 'hgp17290_data' AS table_name, COUNT(*) FROM table_1
) 

Answer 1

You've tried this query:

select count(*)
from information_schema.tables
where table_schema = 'hgp17290_data';

But it seems to me, that you don't have to provide a where clause here with the schema name equals to your database name ( hgp17290_data is your database name, not some schema name). Try it simple as:

select count(*)
from information_schema.tables;