left full join

左全连接（left full join）是指以左表为基准，将左表和右表中的所有记录进行连接，如果右表中没有匹配的记录，则右表的字段为空。\[2\]在SQL语句中，可以使用left join或left outer join来实现左全连接的效果。例如，使用left join可以这样写：SELECT t1.aid, t2.bid, t1.aname, t2.bage FROM t_test1 t1 LEFT JOIN t_test2 t2 ON t1.aid = t2.bid。这样就可以得到左全连接的结果。
#### 引用[.reference_title]
- *1* [left join(左连接)、right join(右连接)、full join(全连接)、inner join(内连接)、cross join(笛卡尔积)...](https://blog.csdn.net/qq_39072649/article/details/104551392)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insertT0,239^v3^insert_chatgpt"}} ] [.reference_item]
- *2* *3* [内连接（join、inner join ）、左连接（left join） 、全连接（full join）](https://blog.csdn.net/x18094/article/details/121780978)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insertT0,239^v3^insert_chatgpt"}} ] [.reference_item]
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