Basic query of Oracle tables

Basic query of Oracle tables

Oracle Paging

1. rownum Paging

Select * from emp;

Select a1. *, rownum rn from (Select * from emp) a1;

2. Display rownum (allocated by oracle)

Select a1. *, rownum rn from (Select * from emp) a1 where rownum <= 10;

Select * from (Select a1. *, rownum rn from (Select * from emp) a1 where rownum <= 10) where rn> = 6;

Several query changes

A. Specify the query column. You only need to modify the subquery at the innermost layer.

B. You only need to modify the subquery at the innermost layer.

Oracle table queries include simple basic queries, complex table queries, multi-table queries, self-join queries, subqueries, and merge queries.