INSERT INTO...SELECT...WHERE 如果条件失败则为 null

发布于 2025-01-03 17:46:38 字数 330 浏览 2 评论 0原文

我正在尝试执行类似以下操作：

INSERT INTO `File` (`Name`, `Owner`) 
SELECT @File, `Users`.Id
FROM `Users`
WHERE `Users`.`Name` = @UserName

但是，如果 Users 表中没有匹配项，我希望它仍然插入文件但具有空值。就像在 Users 表上执行 LEFT JOIN 一样，用 ON 替换 WHERE。但我不能只使用 LEFT JOIN，因为我没有可以连接它的表。谁能帮我解决如何在不将其分成两个单独的查询的情况下做到这一点？

这是专门针对 SQLite 的。

原文

I'm attempting to do something like the following:

INSERT INTO `File` (`Name`, `Owner`) 
SELECT @File, `Users`.Id
FROM `Users`
WHERE `Users`.`Name` = @UserName

However, if there is no match in the Users table, I would like it to still insert the file but with a null value. So like performing a LEFT JOIN on the Users table with ON replacing the WHERE. But I can't just use a LEFT JOIN because I don't have a table to join it to. Can anyone help me out in how I could do this without breaking it into two separate queries?

This is specifically for SQLite.

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亚希 2025-01-10 17:46:38

也许这样的事情可以解决问题：

INSERT INTO `File` (`Name`, `Owner`) 
SELECT @File, `Users`.Id
FROM (SELECT @UserName as Name) notable
left join `Users` on `Users`.`Name` = notable.Name

Maybe something like this could do the trick:

INSERT INTO `File` (`Name`, `Owner`) 
SELECT @File, `Users`.Id
FROM (SELECT @UserName as Name) notable
left join `Users` on `Users`.`Name` = notable.Name

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