Lock table range for select in "Database series" MySQL

Because the InnoDB preset is Row-level lock, MySQL executes row lock only when the primary key is explicitly specified, otherwise MySQL will execute table lock.

1, explicitly specify the primary key is a row lock

2, explicitly specify the primary key, if no data is not locked

3, no primary key, table lock

4, the primary key is not clear, table lock

Note: Myasim only supports table-level locks, INNERDB supports row-level locks, and data that is added (row-level/table-level Lock) locks cannot be locked by other transactions. Nor can it be modified by other transactions.

Lock table range for select in "Database series" MySQL