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我有兩個表:SQL Server的基本加盟
- Currencies1(172行)
- Currencies2(278行)
我只想要一個連接返回172行,但:
SELECT
Currencies1.*, Currencies2.*
FROM
Currencies1
INNER JOIN
Currencies2 ON Currencies1.AlphabeticCode = Currencies2.CurrencyCode;
返回258行
SELECT Currencies1.*, Currencies2.*
FROM Currencies1
LEFT JOIN Currencies2 ON Currencies1.AlphabeticCode = Currencies2.CurrencyCode;
返回268行
SELECT Currencies1.*, Currencies2.*
FROM Currencies1
LEFT JOIN Currencies2 ON Currencies1.AlphabeticCode = Currencies2.CurrencyCode;
返回278行
我不知道這是爲什麼。
感謝您的答覆,我當然在表格Currencies2(例如所有的歐元國家)有重複。我明白你爲什麼加入前1名選擇,但我只是認爲必須有一個更簡單的方法。 。 .guess我錯了。 –