Check for spaces or zeros in all columns in all tables

I have multiple tables in an Oracle schema that have columns with incorrect values: - Number columns where the value is zero, instead of null. - Text columns where the value is a space, instead of null. I’m in the process of cleaning up the data. I will eventually create constraints on the columns to prevent bad data being entered in the first place. But before I do that, I need to find the columns that have existing problems and investigate them. To start, I would like to produce a list of columns that have incorrect values. - For each table in a schema, provide a list of columns that have zeros or spaces as values. > table_name column_name datatype value count > —————————————————————————————————-————————————-———————- > roads width number 0 500 > sidewalks description varchar2 [space] 10000 > sidewalks const_year number 0 2000 Question: What would it take to produce a list like this in Oracle? *(Note: I’m a public works technician by day, not a database administrator. Layman’s terms would be appreciated.)*