Question

I have 3 tables that look something like this:

Table1 Users:

• ID
• Name
• Score

Table2 Game:

• ID
• Name
• Fouls

Table 3 Game2

• ID
• Name
• Fouls

What I would like to do is to in Table1, select all users.
Then select all data where Table1.Name = Table2.Name OR Table1.Name = Table3.Name but with higher priority to Table2, so if there is a match Table1.Name = Table2.Name no join from Table 3 will be made. Then when I’ve selected the correct that I also would like to count the totalt sum of Score and Fouls.

How is this done in SQL and is it possible? I am using MSSQL

Answer 1

SELECT
  SUM(t1.Score) AS TotalScore,
  SUM(COALESCE(t2.Fouls, t3.Fouls)) AS TotalFouls
FROM Table1 t1
  LEFT JOIN Table2 t2 ON t2.Name = t1.Name
  LEFT JOIN Table3 t3 ON t3.Name = NULLIF(t1.Name, t2.Name)