How do I see all foreign keys to a table or column?

Question

In MySQL, how do I get a list of all foreign key constraints pointing to a particular table? a particular column? This is the same thing as this Oracle question, but for MyS

Answer 1

This solution will not only display all relations but also the constraint name, which is required in some cases (e.g. drop contraint):

select
    concat(table_name, '.', column_name) as 'foreign key',
    concat(referenced_table_name, '.', referenced_column_name) as 'references',
    constraint_name as 'constraint name'
from
    information_schema.key_column_usage
where
    referenced_table_name is not null;

If you want to check tables in a specific database, at the end of the query add the schema name:

select
    concat(table_name, '.', column_name) as 'foreign key',
    concat(referenced_table_name, '.', referenced_column_name) as 'references',
    constraint_name as 'constraint name'
from
    information_schema.key_column_usage
where
    referenced_table_name is not null
    and table_schema = 'database_name';

Likewise, for a specific column name, add

and table_name = 'table_name

at the end of the query.

Inspired by this post here