Oracle Basic SQL 014 Study Tips
Sub-queries in select can be converted to left join (use_hj/use_nl)
Tips: The execution plan has the OUTER
keyword
标量子查询可以转left join外连接(use_hj/use_nl)
Tips:
OUTER
关键字Oracle Basic SQL 013 Study Tips
Remove characters from a string
Split strings and numbers
Oracle Basic SQL 012 Study Tips
Generate a continuous number
Query iterate over the string one by one
Oracle Basic SQL 011 Study Tips
Delete the same contents.
Oracle Basic SQL 010 Study Tips
Multi-table association update, Please use merge into or update via VIEW.
MERGE INTO Tips.
merge into xxx
using ()
on ()
when matched then
update ...
when not matched then
insert ... values ...
Oracle Basic SQL 009 Study Tips
Oracle Basic SQL 008 Study Tips
INSERT default value.
Use view to protect default value.
Oracle Basic SQL 007 Study Tips
List department name with only department name and no employees in it.
eg. department_id: 170 (Manufacturing) there is NOT employees in this department.
Oracle Basic SQL 006 Study Tips
list employee infor and list the manager’s name.
Oracle Basic SQL 005 Study Tips
Oracle Basic SQL 004 Study Tips
Oracle Basic SQL 003 Study Tips
HASH JOIN SEMI