sql - SQL query to retrieve columns from different tables in Visual Basic 2010?

Question

I want a SQL query that retrieves columns from different tables in Visual Basic 2010.

I have four tables like this:

1. tblTeacher consists of

   • TID (pk)
   • TName

2. tblSubject consists of

   • SID (pk)
   • subName
   • TID (fk)
   • TMID (fk)

3. tblTime consists of

   • TMID (pk)
   • TMValue

4. tblLecture consists of

   • LecID (pk)
   • LecDate
   • TID (fk)
   • subID (fk)
   • TMID (fk)

tblLecture is for registered Lectures. There is a one-to-many relationship between the tables, wheretblLecture is many. Now my question is:

I want a SQL query that retrieves the registered Lectures and returns columns LecID, LecDate, TName, subName, TMValue. I want to view the results in a DataGridView.

How can I call this SQL in my project please? (In my project, I use an Access database and SQL.)

Answer 1

您必须将表连接在一起，如下所示：

SELECT LecID,LecDate,TName,subName,TMValue
FROM tblLecture l, tblTeacher t, tblSubject s, tblTime i
WHERE l.TID=t.TID
AND   l.subID=s.SID
AND   l.TMID=i.TMID

此外，我想知道您的 tblTime 表。你确定你需要它吗？