Perform any DML/DDL operations on selective tables, selective columns and a mix of those

em_cross_en.sql

-- A simple script that allows you to perform update and delete operations with optional where clause but mainly giving
-- you the flexibilty of doing so across multiple db, tables and columns

do $$
declare
    selectrow record;
begin
for selectrow in
    select
      'DELETE FROM '|| t.mytable || ' WHERE ' || t.mytable ||'.sampledate > ''12-31-2018''' as script 
   from 
      ( 
        select tablename as mytable from pg_tables where schemaname = 'public' and tablename in (SELECT table_name 
				FROM information_schema.columns 
				WHERE table_schema='public' AND column_name='sampledate')
      ) t
loop
execute selectrow.script;
end loop;
end $$

This is a very specific example, my bad!