19 lines
686 B
Markdown
19 lines
686 B
Markdown
# lec6
|
|
|
|
## Lab activity
|
|
|
|
This lecture features a lab activity in the lab/ directory named: `courses-ddl.sql` with instructions in `simple-joins-lab.pdf`.
|
|
|
|
* Note: Just make sure to read int courses-ddl.sql first then courses-small.sql second otherwise there will be random errors.(I'm not taking responsibility for that garbage so don't flame me)
|
|
|
|
## Natural Joins
|
|
|
|
`Natural Joins`: allows us to join tables while getting rid of duplicate columns automatically.
|
|
|
|
Form:
|
|
|
|
```
|
|
select columns_[...] from tableLeft natural join tableRight
|
|
```
|
|
While ther is no need to write extra `where` statements there is also the issue where there may be accidental matches since attributes are dropped.
|