CREATE TABLE t1(f1 INT NOT NULL,
f2 INT NOT NULL,
f3 INT AS (f2 * f2) VIRTUAL,
INDEX idx (f2))engine=innodb;
CREATE TABLE t2(f1 INT NOT NULL, f2 INT NOT NULL,
f3 VARCHAR(10),
INDEX(f1))ENGINE=INNODB;
INSERT INTO t1(f1, f2) VALUES(1, 1);
select @@alter_algorithm;
@@alter_algorithm
NOCOPY
# Add column at the end of the table
ALTER TABLE t1 ADD COLUMN f4 char(100) default "BIG WALL";
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
# Change virtual column expression
ALTER TABLE t1 CHANGE f3 f3 INT AS (f2 * f2) VIRTUAL;
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
# Add virtual column
ALTER TABLE t1 ADD COLUMN f5 INT AS (f2) VIRTUAL;
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
# Rename Column
ALTER TABLE t1 CHANGE f3 vcol INT AS (f2) VIRTUAL;
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
# Rename table
ALTER TABLE t1 RENAME t3;
affected rows: 0
# Drop Virtual Column
ALTER TABLE t3 DROP COLUMN vcol;
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
# Column length varies
ALTER TABLE t2 CHANGE f3 f3 VARCHAR(20);
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
SET foreign_key_checks = 0;
affected rows: 0
ALTER TABLE t3 ADD FOREIGN KEY `fidx`(f2) REFERENCES t2(f1);
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
SET foreign_key_checks = 1;
affected rows: 0
ALTER TABLE t3 DROP FOREIGN KEY `fidx`;
affected rows: 0
info: Records: 0  Duplicates: 0  Warnings: 0
DROP TABLE t3, t2;
affected rows: 0