From c8d18c7c0a35689ff3c2dbf2958760f57964da7c Mon Sep 17 00:00:00 2001 From: yushao21 Date: Mon, 13 Apr 2026 03:29:40 +0000 Subject: [PATCH] =?UTF-8?q?update=2012-dev-guide/12-4-2-data-select-multi-?= =?UTF-8?q?table.md.=20=E7=BC=BA=E5=B0=91=E6=9D=A1=E4=BB=B6=E4=BA=86?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: yushao21 --- 12-dev-guide/12-4-2-data-select-multi-table.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/12-dev-guide/12-4-2-data-select-multi-table.md b/12-dev-guide/12-4-2-data-select-multi-table.md index c4141d5..0f4f423 100644 --- a/12-dev-guide/12-4-2-data-select-multi-table.md +++ b/12-dev-guide/12-4-2-data-select-multi-table.md @@ -173,7 +173,7 @@ FROM country ### 左外连接排除B部分 若要排除B部分，则在WHRER语句中添加`IS NULL`条件，如下： ```sql -SELECT * FROM A LEFT JOIN B ON A.key = B.key WHRER IS NULL; +SELECT * FROM A LEFT JOIN B ON A.key = B.key WHRER B.key IS NULL; ``` 例如查询没有对应国家的城市 ```sql @@ -270,7 +270,7 @@ LIMIT 5; ### 右外连接排除A部分 若要排除A部分，则在WHRER语句中添加`IS NULL`条件，如下： ```sql -SELECT * FROM A RIGHT JOIN B ON A.key = B.key WHRER IS NULL; +SELECT * FROM A RIGHT JOIN B ON A.key = B.key WHRER A.key IS NULL; ``` 例如查询没有对应城市的国家 ```sql -- Gitee