0
我有两个表:SQL Server的基本加盟
- Currencies1(172行)
- Currencies2(278行)
我只想要一个连接返回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
我不知道这是为什么。
感谢您的答复,我当然在表格Currencies2(例如所有的欧元国家)有重复。我明白你为什么加入前1名选择,但我只是认为必须有一个更简单的方法。 。 .guess我错了。 –