Differences between primary keys, indexes, and paging in Oracle and MySQL

Differences between primary keys, indexes, and pages of Oracle and MySQL:

1. Primary keys. Oracle cannot implement auto-increment, and mysql can implement auto-increment.

Oracle new sequence, SEQ_USER_Id.nextval

2. Index:

Mysql index starts from 0 and Oracle starts from 1.

3. Paging,

Mysql: select * from user order by desc limit n, m.

Indicates that a total of m data records are searched from the nth data records.

Oracle: select * from user

Select rownum a * from (select * from user))

Select * from (select rownum a. * from (select * from user))

Where r between n, m.

N indicates that m data entries are queried from the nth data entries.