计算机科学

Remove duplicates

# Reference from https://www.runoob.com/mysql/mysql-handling-duplicates.html, 201910210056
CREATE TABLE tmp SELECT DISTINCT * from table_name;
DROP TABLE table_name;
ALTER TABLE tmp RENAME TO table_name;

And You can also use the sql command CREATE TABLE tmp SELECT field_1, ..., field_X from table_name GROUP BY field_1, ..., field_X; to repalce the first command.

Questions need to pay attenion

  1. Sets all field’s type to varchar if you don’t know the access data’s type.

  2. Adds single quotes for all new data in the insert, update sql command if you not sure the which fields need the quotes.