Go to the editor and turn on dbms_output, then run this.
declare
RowCount Number;
Qry Varchar2(300);
Cursor Tables is
select owner, table_name, column_name
from dba_tab_columns
where column_name = 'SOURCEID';
begin
for TableRec in Tables loop
begin
Qry := 'select count(*) ' ||
'from ' || TableRec.Owner || '.' || TableRec.Table_Name || ' ' ||
'where ' || TableRec.Column_Name || ' = ''PE_DM_MW''';
execute immediate Qry into RowCount;
dbms_output.put_line(TableRec.Owner || '.' || TableRec.Table_Name || ' ' || To_Char(RowCount) || ' Rows.');
exception
when no_data_found then
null;
when others then
dbms_Output.put_line(qry);
end;
end loop;
end;