添加联合主键

CREATE TABLE c
(
  id INT NOT NULL,
  nameid VARCHAR(10) NOT NULL,
  address VARCHAR(5) NOT NULL
);

ALTER TABLE c ADD PRIMARY KEY (id,nameid);

 

CREATE TABLE c
(
  id INT NOT NULL,
  nameid VARCHAR(10) NOT NULL,
  address VARCHAR(5) NOT NULL,
  PRIMARY KEY(id,nameid)
);