Mysql – How to make a empty MySQL table

For InnoDB, the following seems to work: create the new empty database, then rename each table in turn into the new database:

RENAME TABLE old_db.table TO new_db.table;

You will need to adjust the permissions after that.

For scripting in a shell, you can use either of the following:

mysql -u username -ppassword old_db -sNe 'show tables' | while read table; \ 
    do mysql -u username -ppassword -sNe "rename table old_db.$table to new_db.$table"; done

OR

for table in `mysql -u root -ppassword -s -N -e "use old_db;show tables from old_db;"`; do mysql -u root -ppassword -s -N -e "use old_db;rename table old_db.$table to new_db.$table;"; done;

Notes:

• There is no space between the option -p and the password. If your database has no password, remove the -u username -ppassword part.

• If some table has a trigger, it cannot be moved to another database using above method (will result Trigger in wrong schema error). If that is the case, use a traditional way to clone a database and then drop the old one:

  mysqldump old_db | mysql new_db

• If you have stored procedures, you can copy them afterwards:

  mysqldump -R old_db | mysql new_db

Timestamps in MySQL are generally used to track changes to records, and are often updated every time the record is changed. If you want to store a specific value you should use a datetime field.

If you meant that you want to decide between using a UNIX timestamp or a native MySQL datetime field, go with the native format. You can do calculations within MySQL that way ("SELECT DATE_ADD(my_datetime, INTERVAL 1 DAY)") and it is simple to change the format of the value to a UNIX timestamp ("SELECT UNIX_TIMESTAMP(my_datetime)") when you query the record if you want to operate on it with PHP.