mysql – How, when inserting data, add only records with a unique column value, and if the value exists, update the record?

Question:

there is a table with the following structure:

-----------------------------
ID     IP          Timestamp
-----------------------------
1      127.0.0.1   1111111111
2      127.0.0.1   1111111112

You need to do the following: new records should not be written to the table, for which the IP corresponds to the IP in the table, but the Timestamp in the table should only be updated , otherwise – a new record with a new IP is added

-----------------------------
ID     IP          Timestamp
-----------------------------
1      127.0.0.1   1111111112

tried putting индекс->unique , but then Timestamp is not updated

how to implement this business without sending 2 requests?

Answer:

I propose to put a unique key on the ip column, set AUTO_INCREMENT on id ( but it is better to remove this column altogether) and use a query like INSERT ... ON DUPLICATE KEY UPDATE

insert into `table_name` (`ip`, `last_modified`) 
       values ($ip, UNIX_TIMESTAMP()) 
       on duplicate key update `last_modified`=UNIX_TIMESTAMP()