LEFT JOIN、RIGHT JOIN、INNER JOIN、OUTER JOIN 一张图看懂 SQL 7 种JOIN用法

LEFT JOIN、RIGHT JOIN、INNER JOIN、OUTER JOIN 相关的 7 种用法。文章源自菜鸟学院-https://www.cainiaoxueyuan.com/sjk/26606.html

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具体分解如下：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/sjk/26606.html

1.INNER JOIN（内连接）

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

2.LEFT JOIN（左连接）

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

3.RIGHT JOIN（右连接）

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

4.OUTER JOIN（外连接）

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

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

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

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

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

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

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SELECT <select_list>
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