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                ThinkChat2.0新版上線,更智能更精彩,支持會話、畫圖、視頻、閱讀、搜索等,送10W Token,即刻開啟你的AI之旅 廣告
                **全外連接(全連接)**:將會返回所有表中符合 ON 語句條件的所有記錄。如果任一表的指定字段沒有符合條件的值的話,那么就使用 NULL 值替代。 ```sql select * from left_tbl; +--------------+----------------+---------------+--+ | left_tbl.id | left_tbl.name | left_tbl.age | +--------------+----------------+---------------+--+ | 1 | 張三 | 20 | | 2 | 李四 | 22 | | 3 | 王五 | 25 | +--------------+----------------+---------------+--+ select * from right_tbl; +---------------+-----------------+----------------+--+ | right_tbl.id | right_tbl.name | right_tbl.age | +---------------+-----------------+----------------+--+ | 1 | 張三 | 20 | | 2 | 李四 | 22 | | 4 | 王五 | 25 | +---------------+-----------------+----------------+--+ ############ 全連接 ############## -- 左表、右表全查詢,左表沒有的用NULL填充,右表沒有的也用NULL填充 -- full join 是 full outer join 的簡寫 select * from left_tbl lt full join right_tbl rt on lt.id=rt.id; +--------+----------+---------+--------+----------+---------+--+ | lt.id | lt.name | lt.age | rt.id | rt.name | rt.age | +--------+----------+---------+--------+----------+---------+--+ | 1 | 張三 | 20 | 1 | 張三 | 20 | | 2 | 李四 | 22 | 2 | 李四 | 22 | | 3 | 王五 | 25 | NULL | NULL | NULL | | NULL | NULL | NULL | 4 | 王五 | 25 | +--------+----------+---------+--------+----------+---------+--+ ```
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