Query below finds all tables that have 'username' column.

See also tables that don't have a column with specific name.

Query

select t.table_schema,
       t.table_name
from information_schema.tables t
inner join information_schema.columns c 
           on c.table_name = t.table_name 
           and c.table_schema = t.table_schema
where c.column_name = 'username'
      and t.table_schema not in ('information_schema', 'pg_catalog')
      and t.table_type = 'BASE TABLE'
order by t.table_schema;

Columns

• table_schema - name of schema of found table
• table_name - name of found table

Rows

• One row represents a table
• Scope of rows: all found tables
• Ordered by table schema

Sample results

List of tables that have 'username' column.