LEFT OUTER JOIN问题

Question

我有一个错误，我不能理解，如果有人可以向我解释这个问题，因为它阻止我继续我的程序。

错误是说我在JOIN上有语法错误

代码

using (OleDbDataAdapter query_prof = new OleDbDataAdapter("SELECT aspnet_Users.AplicationId, aspnet_User.UserName, aspnet_User.LastActivityDate FROM (aspnet_Users LEFT OUTER JOIN UserProfile ON aspnet_User.UserName = UserProfile.UserName) WHERE (UserProfile.UserName IS NULL)", conn))
{
    query_prof.Fill(dt);
}

Answer 1

从from子句中省略括号：

FROM (aspnet_Users LEFT OUTER JOIN UserProfile ON aspnet_User.UserName = UserProfile.UserName)

你应该这样做：

FROM aspnet_Users LEFT OUTER JOIN UserProfile ON aspnet_User.UserName = UserProfile.UserName