如何在MySQL中显示表的唯一约束？

Question

我创造了它们,但我忘了它们是哪些.

我只想

1. 让他们看.
2. 删除表上的所有约束.

Answer 1

select distinct CONSTRAINT_NAME
from information_schema.TABLE_CONSTRAINTS
where table_name = 'table_name' and constraint_type = 'UNIQUE';

Answer 2

这不会产生优雅的输出，但很容易记住：

SHOW CREATE TABLE table_name;

Answer 3

select distinct CONSTRAINT_NAME
from information_schema.TABLE_CONSTRAINTS
where CONSTRAINT_SCHEMA = 'mysql'

Answer 4

此查询返回主键、唯一键和外键：

show indexes from table_name;