CREATE TABLE bug48024(a int PRIMARY KEY,b int NOT NULL,KEY(b)) ENGINE=InnoDB;
CREATE TABLE bug48024_b(b int PRIMARY KEY) ENGINE=InnoDB;
ALTER TABLE bug48024 /*/ADD CONSTRAINT FOREIGN KEY(c) REFERENCES(a),/*/
ADD CONSTRAINT FOREIGN KEY(b) REFERENCES bug48024_b(b);
DROP TABLE bug48024,bug48024_b;
CREATE TABLE bug48024(a int PRIMARY KEY,b int NOT NULL,KEY(b)) ENGINE=InnoDB;
CREATE TABLE bug48024_b(b int PRIMARY KEY) ENGINE=InnoDB;
ALTER TABLE bug48024 /*/ADD CONSTRAINT FOREIGN KEY(c) REFERENCES(a),/*/
ADD CONSTRAINT FOREIGN KEY(b) REFERENCES bug48024_b(b)|
DROP TABLE bug48024,bug48024_b;