-- Finding difference in values for some key
SELECT * from A a,b WHERE a.id = b.id AND NOT a.name = b.name;

--Returns one row for each CHECK, UNIQUE, PRIMARY KEY, and/or FOREIGN KEY
SELECT *
    FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
    WHERE CONSTRAINT_NAME='XYZ'


--Returns one row for each FOREIGN KEY constrain
SELECT *
    FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS
    WHERE CONSTRAINT_NAME='XYZ'


--Returns one row for each CHECK constraint
SELECT *
    FROM INFORMATION_SCHEMA.CHECK_CONSTRAINTS
    WHERE CONSTRAINT_NAME='XYZ'