SQl 結單金額

Question

嘿伙計們，我正在嘗試對這些表格求和，但我無法弄清楚我做錯了什么

我的第一張桌子是：

Reserve
ReserveID   MembershipID   PlayerCount   Time    CourseID

我的第二張桌子是

Courses
CourseID   Name

我正在嘗試的 sql 聲明在這里：

Select Sum(Reserve.Player_Count)Total
From Reserve 
Left Join Courses 
On Courses.CourseID = Reserve.ReserveID 
Where Time = "2012-04-09 07:10:00" 
And Courses.Name = "Lake" (or I had Courses.CourseId = "1")

Answer 1

你好象混了別名。 避開他們

Select Sum(Reserve.Player_Count)Total
From Reserve 
Left Join Courses 
On Courses.CourseID = Reserve.ReserveID 
Where Reserve.Time = "2012-04-09 07:10:00" 
--     ^ Right here  
And Courses.Name = "Lake" (or I had Courses.CourseId = "1")