使用information_schema.table_constraints表获取每个表上定义的约束的名称：

select *
from information_schema.table_constraints
where constraint_schema = 'YOUR_DB'

使用information_schema.key_column_usage表获取这些约束中的字段：

select *
from information_schema.key_column_usage
where constraint_schema = 'YOUR_DB'

如果您要讨论外键约束，请使用information_schema.referential_constraints：

select *
from information_schema.referential_constraints
where constraint_schema = 'YOUR_DB'