Blocking '0000-00-00' from MySQL Date Fiel

Question

I have a database where old code likes to insert '0000-00-00' in Date and DateTime columns instead of a real date. So I have the following two questions:

1. Is there anything that I could do on the db level to block this? I know that I can set a column to be not-null, but that does not seem to be blocking these zero values.
2. What is the best way to detect the existing zero values in date fields? I have about a hundred tables with 2-3 date columns each and I don't want to query them individually.

Followup:

The default is already set to null. A long time ago, the default was '0000-00-00'. Some code still explicitly places '0000-00-00'. I would prefer to force that code to throw an error so I could isolate and remove it.

Answer 1

Assuming you can't easily fix the data and "SET sql_mode = 'NO_ZERO_DATE';", you could create a view on the table...

CREATE VIEW filter AS
SELECT other_column, 
CASE 
  WHEN realtable.dodgy_date = 0 THEN NULL 
  ELSE realtable.dodgy_date
END AS dodgy_date
FROM realtable;