365 Days of Daily Coding: Day 110

Is it possible for LEFT JOIN and FULL OUTER JOIN to produce the same results? Why or why not?

LEFT JOIN: Returns all the records that are common between Table 1 and Table 2 as well as the non-matching records from Table 1.

FULL OUTER JOIN: Returns all the records that are common between Table 1 and Table 2 as well as the non-matching records from Table 1 and Table 2.

Table 1

ID	Name
1	Karma
2	Dolma
3	Tashi

Table 2

ID	Books
1	Start With Why by Simon Sinek
1	Sherlock Holmes by Sir Arthur Conan Doyle
2	5 People You Meet In Heaven by Mitch Albom
4	Have a Little Faith by Mitch Albom

Left Join of Table 1 and Table 2

ID	Name	ID	Books
1	Karma	1	Start With Why by Simon Sinek
1	Karma	1	Sherlock Holmes by Sir Arthur Conan Doyle
2	Dolma	2	5 People You Meet In Heaven by Mitch Albom
3	Tashi	Null	Null

Full Outer Join of Table 1 and Table 2

ID	Name	ID	Books
1	Karma	1	Start With Why by Simon Sinek
1	Karma	1	Sherlock Holmes by Sir Arthur Conan Doyle
2	Dolma	2	5 People You Meet In Heaven by Mitch Albom
3	Tashi	Null	Null
Null	Null	4	Have a Little Faith by Mitch Albom

To answer the question, yes I do think it is possible for LEFT JOIN and LEFT OUTER JOIN to produce the same results. This can happen when every record in Table 1 has a matching record in Table 2.

Table 1

ID	Name
1	Karma
2	Dolma
3	Tashi

Table 2

ID	Books
1	Start With Why by Simon Sinek
1	Sherlock Holmes by Sir Arthur Conan Doyle
2	5 People You Meet In Heaven by Mitch Albom
3	The Magical Strings of Frankie Presto by Mitch Albom

LEFT JOIN

ID	Name	ID	Books
1	Karma	1	Start With Why by Simon Sinek
1	Karma	1	Sherlock Holmes by Sir Arthur Conan Doyle
2	Dolma	2	5 People You Meet In Heaven by Mitch Albom
3	Tashi	3	The Magical Strings of Frankie Presto by Mitch Albom

FULL OUTER JOIN

ID	Name	ID	Books
1	Karma	1	Start With Why by Simon Sinek
1	Karma	1	Sherlock Holmes by Sir Arthur Conan Doyle
2	Dolma	2	5 People You Meet In Heaven by Mitch Albom
3	Tashi	3	The Magical Strings of Frankie Presto by Mitch Albom