SQL optimization entries

(1) Avoid using '*' in the SELECT clause '*':
During the parsing process, ORACLE converts '*' into all column names in sequence. This is done by querying the data dictionary, which means it takes more time.

(2) Try to use COMMIT as much as possible:
As long as possible, use COMMIT as much as possible in the program, so that the program's performance is improved, and the demand will also be reduced by the resources released by COMMIT:
Resources released by COMMIT:
A. Information used to restore data on the rollback segment.
B. Locks obtained by Program Statements
C. Space in redo log buffer
D. ORACLE manages the internal costs of the above three types of resources

(3) Use the table Alias (Alias ):
When connecting multiple tables in an SQL statement, use the table alias and prefix the alias on each Column. in this way, the parsing time can be reduced and the syntax errors caused by Column ambiguity can be reduced.