一张图看懂 SQL 的各种 join 用法

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INNER JOIN（内连接）

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SELECT  
FROM Table_A A
INNER JOIN Table_B B
ON A.Key = B.Key

LEFT JOIN（左连接）

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SELECT 
FROM Table_A A
LEFT JOIN Table_B B
ON A.Key = B.Key

RIGHT JOIN（右连接）

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SELECT 
FROM Table_A A
RIGHT JOIN Table_B B
ON A.Key = B.Key

OUTER JOIN（外连接）

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SELECT 
FROM Table_A A
FULL OUTER JOIN Table_B B
ON A.Key = B.Key

LEFT JOIN EXCLUDING INNER JOIN（左连接-内连接）

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SELECT  
FROM Table_A A
LEFT JOIN Table_B B
ON A.Key = B.Key
WHERE B.Key IS NULL

RIGHT JOIN EXCLUDING INNER JOIN（右连接-内连接）

image.png

SELECT 
FROM Table_A A
RIGHT JOIN Table_B B
ON A.Key = B.Key
WHERE A.Key IS NULL

OUTER JOIN EXCLUDING INNER JOIN（外连接-内连接）

image.png

SELECT 
FROM Table_A A
FULL OUTER JOIN Table_B B
ON A.Key = B.Key
WHERE A.Key IS NULL OR B.Key IS NULL