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C# 用于从其他表检索的SQL语法?_C#_Asp.net_Mysql_Sql - Fatal编程技术网

C# 用于从其他表检索的SQL语法?

C# 用于从其他表检索的SQL语法?,c#,asp.net,mysql,sql,C#,Asp.net,Mysql,Sql,您好,我有两个表用户和图片我试图从我的图片表中提取路径名(userid=1)在与pk相关的两个表中都是相同的,但我不确定如何从用户表中选择firstname等并从图片表中选择picturepath 我还想知道,如果我使用注释掉的行,是否可以正确设置img路径 OdbcCommand cmd = new OdbcCommand("SELECT User.FirstName, User.SecondName, User.Aboutme, User.DOB, Pictures.pict

您好,我有两个表用户和图片我试图从我的图片表中提取路径名(userid=1)在与pk相关的两个表中都是相同的,但我不确定如何从用户表中选择firstname等并从图片表中选择picturepath

我还想知道,如果我使用注释掉的行,是否可以正确设置img路径

        OdbcCommand cmd = new OdbcCommand("SELECT User.FirstName, User.SecondName, User.Aboutme, User.DOB, Pictures.picturepath FROM User LEFT JOIN Pictures ON User.UserID = Pictures.UserID WHERE User.UserID=1", cn);
        OdbcDataReader reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            Name.Text = String.Format("{0} {1}", reader.GetString(0), reader.GetString(1));
            Aboutme.Text = String.Format("{0}", reader.GetString(2));
            Age.Text = String.Format("{0}", reader.GetString(3));
            Image1.ImageUrl = String.Format("{0}", reader.GetString(4));
        }


    }
}

要在一个查询中从两个相关表中获取数据,可以使用联接:

SELECT
    User.FirstName,
    User.SecondName,
    User.Aboutme,
    User.DOB,
    Picture.PicturePath
FROM User
LEFT JOIN Pictures
ON User.UserID = Pictures.UserID
WHERE User.UserID=1

然后,是的,您可以取消注释最后一行。

为什么要将
D[ate]O[f]B[irth]
赋值给名为
Age
的字段?这是不一样的,但以后会更改未知列“User.User”in“on子句”no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no?