How Can I Efficiently Join Three Tables in SQL to Retrieve Comprehensive Student Application Data?

SQL multi-table connection skills: integrating student application data

In database management, it is often necessary to integrate data from multiple tables to obtain a more comprehensive view. SQL connection statements are born for this purpose. This article explores how to join three tables to obtain more detailed student application information and dorm preference data.

The initial query provided by the user successfully inner joins two tables: one containing student data and the other containing their dorm preferences. However, to get the complete results, a third table is needed to convert HallIDs into actual HallNames. For this we can use additional inner joins.

The following modified query achieves this goal:

SELECT
  s.StudentID,
  s.FName,
  s.LName,
  s.Gender,
  s.BirthDate,
  s.Email,
  r.HallPref1,
  r.HallPref2,
  r.HallPref3,
  h.HallName
FROM
  dbo.StudentSignUp AS s
INNER JOIN RoomSignUp.dbo.Incoming_Applications_Current AS r
  ON s.StudentID = r.StudentID
INNER JOIN HallData.dbo.Halls AS h
  ON r.HallPref1 = h.HallID

This updated query introduces an inner join on the Halls table, using the HallID in the preference table as the matching condition. As a result, we now have a more informative result that contains actual dorm names, not just HallIDs.

By adding another inner join to the initial query, we were able to join the various tables and retrieve the required data from all three data sources. This demonstrates the power of SQL connections in accessing and manipulating data from multiple tables to gain valuable insights.

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