MYSQL LOCK in SHARE mode&for UPDATE

SELECT ... LOCK in SHARE mode sets a shared mode lock on the rows read. A Shared mode lock enables other sessions to read the rows is not to modify them. The rows read is the latest available, so if they belong to another transaction that have not yet committed, the Read bloc KS until that transaction ends.

SELECT ... For UPDATE sets a exclusive lock on the rows read. An exclusive lock prevents other sessions from accessing the rows for reading or writing.

MYSQL LOCK in SHARE mode&for UPDATE