Is it possible to automatically generate a Unix millisecond timestamp in MySQL 5.7

Question

I have created a created_time field with BIGINT in a MySQL 5.7 table, now I want to auto generate a Unix millisecond timestamp when I insert a record. Is it possible to do this? I have tried the code below but it failed:

ALTER TABLE db.video_info MODIFY COLUMN created_time bigint(20) 
 DEFAULT (ROUND(UNIX_TIMESTAMP(CURTIME(4)) * 1000)) NULL;

• danblack: tip for questions, replace 'tried this but failed' and replace with 'tried this... which generated the error message....'

Answer 1

MySQL 8.0 supports the expression default like you show.

MySQL 5.7 does not support expressions as default. Only NULL, or a constant value, or CURRENT_TIMESTAMP if it's a DATETIME or TIMESTAMP column.

For MySQL 5.7, you have two alternatives:

• Declare the column as created_time datetime(3) default current_timestamp(3).

• Use BIGINT as you are doing, but write a trigger to set the value.

• danblack: ref: documentation on data type defaults