MYSQL设计表时，亟需 两个TIMESTAMP 字段的情况

CREATE TABLE `test_table` (
`id` INT( 10 ) NOT NULL,
`create_time` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`update_time` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE = INNODB;

CREATE TABLE `test_table` (
`id` INT( 10 ) NOT NULL,
`create_time` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
`update_time` TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE = INNODB;

Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause

CREATE TABLE `test_table` (
`id` INT( 10 ) NOT NULL,
`create_time` TIMESTAMP NOT NULL DEFAULT 0,
`update_time` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE = INNODB;

INSERT INTO test_table (id, create_time, update_time) VALUES (1, NULL, NULL);

INSERT INTO test_table (id, update_time) VALUES (1, NULL);

UPDATE test_table (id) VALUES (2);