SQL join в примерах с описанием

Существует несколько базовых, часто используемых join-ов:

• INNER JOIN
• LEFT JOIN
• RIGHT JOIN
• LEFT OUTER JOIN
• RIGHT OUTER JOIN
• FULL OUTER JOIN

1. INNER JOIN:

SQL запрос:

SELECT * FROM 'table_1'
INNER JOIN 'table_2' 
ON 'table_1'.id = 'table_2'.id

2. LEFT JOIN:

SQL запрос:

SELECT * FROM 'table_1'
LEFT OUTER JOIN 'table_2' 
ON 'table_1'.id = 'table_2'.id
WHERE 'table_2'.id IS null

3. RIGHT JOIN:

SQL запрос:

SELECT * FROM 'table_2'
LEFT OUTER JOIN 'table_1' 
ON 'table_2'.id = 'table_1'.id
WHERE 'table_1'.id IS null

4. LEFT OUTER JOIN:

SQL запрос:

SELECT * FROM 'table_1'
LEFT OUTER JOIN 'table_2' 
ON 'table_1'.id = 'table_2'.id

5. RIGHT OUTER JOIN:

SQL запрос:

SELECT * FROM 'table_2'
LEFT OUTER JOIN 'table_1' 
ON 'table_2'.id = 'table_1'.id

6. FULL OUTER JOIN

SQL запрос:

SELECT * FROM 'table_1'
FULL OUTER JOIN 'table_2' ON 'table_1'.id = 'table_2'.id