SQL Server 2022

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DECLARE @T1_Customers TABLE

(T1_Customer_id INT,

T1_FName VARCHAR(50),

T1_LName VARCHAR(50))

INSERT INTO @T1_Customers VALUES

(1,'John','Darwin'),

(2,'Jane','Doe'),

(3,'Bobby','Black')

DECLARE @T2_Classes TABLE

(T2_Class_id INT,

T2_Customer_id INT,

T2_ClassType_id INT,

T2_ClassName VARCHAR(50),

T2_Status VARCHAR(50))

INSERT INTO @T2_Classes VALUES

(1,1,1,'Emergency Medical Dispatch v1','Pass'),

(2,1,2,'Emergency Medical Dispatch Instructor','Pass'),

(3,2,3,'Public Safety Telecommunicator','Pass'),

(4,2,1,'Emergency Medical Dispatch v1','Pass'),

(5,2,1,'Emergency Medical Dispatch v2','Fail')

DECLARE @T3_ClassTypes TABLE

(T3_ClassType_id INT,

T3_ClassType VARCHAR(50))

INSERT INTO @T3_ClassTypes VALUES

(1,'EMD'),

(2,'EMD-I'),

(3,'PST')

--SELECT * FROM @T1_Customers SELECT * FROM @T2_Classes SELECT * FROM @T3_ClassTypes

--FIRST ATTEMPT

SELECT * FROM @T1_Customers

LEFT JOIN @T2_Classes

ON T2_Customer_id = T1_Customer_id

T1_Customer_id	T1_FName	T1_LName	T2_Class_id	T2_Customer_id	T2_ClassType_id	T2_ClassName	T2_Status	T3_ClassType_id	T3_ClassType
1	John	Darwin	1	1	1	Emergency Medical Dispatch v1	Pass	1	EMD
1	John	Darwin	2	1	2	Emergency Medical Dispatch Instructor	Pass	2	EMD-I
2	Jane	Doe	4	2	1	Emergency Medical Dispatch v1	Pass	1	EMD

T1_Customer_id	T1_FName	T1_LName	T2_Class_id	T2_Customer_id	T2_ClassType_id	T2_ClassName	T2_Status	T3_ClassType_id	T3_ClassType
1	John	Darwin	1	1	1	Emergency Medical Dispatch v1	Pass	1	EMD
1	John	Darwin	2	1	2	Emergency Medical Dispatch Instructor	Pass	2	EMD-I
2	Jane	Doe	3	2	3	Public Safety Telecommunicator	Pass	null	null
2	Jane	Doe	4	2	1	Emergency Medical Dispatch v1	Pass	1	EMD
3	Bobby	Black	null	null	null	null	null	null	null

T1_Customer_id	T1_FName	T1_LName	T2_Class_id	T2_Customer_id	T2_ClassType_id	T2_ClassName	T2_Status	T3_ClassType_id	T3_ClassType
1	John	Darwin	1	1	1	Emergency Medical Dispatch v1	Pass	1	EMD
1	John	Darwin	2	1	2	Emergency Medical Dispatch Instructor	Pass	2	EMD-I
2	Jane	Doe	4	2	1	Emergency Medical Dispatch v1	Pass	1	EMD
3	Bobby	Black	null	null	null	null	null	null	null