Complex Joining multiple tables in SQL Server for a fact table - sql

Question

Hi I have 4 dimensions and I am trying to insert multiple data from the dimensions into the fact table.
I have a Gunsales table that contains the majority of the data for the fact table and then primary keys from other tables that I would like to join on. homicide_id from the Homicide table, article_id from the BBC table, incident_id from the Gun_violence table and shooting_id from the School_shooting table. The rest of the data if from the Gunsales table.
INSERT INTO [dbo].[FactGunSales]
(
sale_id,
sale_date,
sale_state,
permit,
hand_gun,
long_gun,
other_gun,
multiple_gun,
incident_id,
homicide_id,
article_id,
shooitng_id)
So logically it is a full join of the Gun_sales table and an inner join for the ID keys in the other table but I am struggling to get this to work.
adding in the DDL for all the tables:
USE [Gun Violence]
GO
DROP TABLE IF EXISTS Gun_Violence
CREATE TABLE Gun_Violence(
incident_id int PRIMARY KEY,
incident_date date,
state_name varchar (50),
city_name varchar(50),
death int ,
injury int ,
)
DROP TABLE IF EXISTS Gun_Sales
CREATE TABLE Gun_Sales(
sale_id int PRIMARY KEY,
sale_date date,
sale_state varchar(50),
permit int,
hand_gun int ,
long_gun int ,
other_gun int ,
multiple_gun int ,
)
DROP TABLE IF EXISTS School_Shootings
CREATE TABLE School_Shootings(
shooting_id int PRIMARY KEY,
shooting_date date,
shooting_state varchar(50),
shooting_city varchar(50),
shooting_death int ,
shooting_injury int,
)
DROP TABLE IF EXISTS Homicide
CREATE TABLE Homicide(
Homicide_id int PRIMARY KEY,
homicide_state varchar(50),
homicide_victims int,
homeicide_date date
)
DROP TABLE IF EXISTS BBC
CREATE TABLE BBC(
ariticle_id int PRIMARY KEY,
article_date date,
article_link varchar(1000),
article_headline varchar(1000),
article_count int,
article_keyword varchar(100),
article_month varchar(10),
article_year int,
article_state varchar(50)
)
Output:
As mentioned above I am trying to create a new fact table that has all columns from the Gun_sales table and the primary keys from the other tables.
Thanks in advance

Answer 1

#RitaMurran Is't true? Do you want Something like this?
USE [Gun Violence]
go
INSERT INTO [dbo].[FACTGUNSALES]
([sale_id],
[sale_date],
[sale_state],
[hand_gun],
[other_gun],
[multiple_gun],
[incident_id],
[homicide_id],
[article_id],
[shooitng_id])
SELECT [sale_id],
[sale_date],
[sale_state],
[hand_gun],
[other_gun],
[multiple_gun],
[dbo].[GUN_VIOLENCE].incident_id,
[dbo].[HOMICIDE].homicide_id,
[dbo].[BBC].ariticle_id,
[dbo].[SCHOOL_SHOOTINGS].shooting_id
FROM [dbo].[GUN_SALES]
LEFT JOIN [dbo].[GUN_VIOLENCE]
ON ( [dbo].[GUN_VIOLENCE].incident_date = [dbo].[GUN_SALES].[sale_date] AND
[dbo].[GUN_VIOLENCE].state_name = [dbo].[GUN_SALES].[sale_state] )
LEFT JOIN [dbo].[SCHOOL_SHOOTINGS]
ON ( [dbo].[SCHOOL_SHOOTINGS].shooting_date = [dbo].[GUN_SALES].[sale_date] AND
[dbo].[SCHOOL_SHOOTINGS].shooting_state = [dbo].[GUN_SALES]. [sale_state] )
LEFT JOIN [dbo].[HOMICIDE]
ON ( [dbo].[HOMICIDE].homeicide_date = [dbo].[GUN_SALES].[sale_date] AND
[dbo].[HOMICIDE].homicide_state = [dbo].[GUN_SALES].[sale_state] )
LEFT JOIN [dbo].[BBC]
ON ( [dbo].[BBC].article_date = [dbo].[GUN_SALES].[sale_date] AND
[dbo].[BBC].[article_state] = [dbo].[Gun_Sales].[sale_state] )
EDIT:
#RitaMurran, I answer your question:
"Is there a way to have only distinct values when the join happens?"
with the example:
DECLARE #tbl_A TABLE (ID_A INT, col_A varChar(10))
INSERT #tbl_A (ID_A,col_A)
SELECT 1 AS ID_A,'aaa' AS col_A UNION ALL
SELECT 2 ,'bbb' UNION ALL
SELECT 3 ,'ccc' UNION ALL
SELECT 4 ,'ddd' UNION ALL
SELECT 5 ,'eee'
DECLARE #tbl_B TABLE (ID_B INT,ID_A_FK INT, col_B varChar(10))
INSERT #tbl_B (ID_B,ID_A_FK,col_B)
SELECT 1 AS ID_B,1 AS ID_A_FK,NULL AS col_B UNION ALL
SELECT 2 ,1 ,NULL UNION ALL
SELECT 3 ,3 ,NULL UNION ALL
SELECT 4 ,3 ,NULL UNION ALL
SELECT 5 ,3 ,NULL
SELECT *
FROM #tbl_A tbA
LEFT JOIN
( select ID_A_FK,col_B FROM #tbl_B GROUP BY ID_A_FK,col_B ) tbB ON tbA.ID_A = tbB.ID_A_FK
The Output:
ID_A col_A ID_A_FK col_B
1 aaa 1 NULL
2 bbb NULL NULL
3 ccc 3 NULL
4 ddd NULL NULL
5 eee NULL NULL
If col_B has value,The output is like this:
INSERT #tbl_B (ID_B,ID_A_FK,col_B)
SELECT 1 AS ID_B,1 AS ID_A_FK,'a1' AS col_B UNION ALL
SELECT 2 ,1 ,'a2' UNION ALL
SELECT 3 ,3 ,'c1' UNION ALL
SELECT 4 ,3 ,'c2' UNION ALL
SELECT 5 ,3 ,'c3'
Output:
ID_A col_A ID_A_FK col_B
1 aaa 1 a1
1 aaa 1 a2
2 bbb NULL NULL
3 ccc 3 c1
3 ccc 3 c2
3 ccc 3 c3
4 ddd NULL NULL
5 eee NULL NULL