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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;
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.
