Looking for query for below output?

Question

Hello Experts,
I have couple of master tables and those are linked with my audit table.
For example, below are 2 master tables,
CREATE TABLE MASTER1 (MASTER1_UID INT IDENTITY(1,1) PRIMARY KEY, MASTER1_VAL VARCHAR(10))
INSERT INTO MASTER1 (MASTER1_VAL) VALUES ('VAL1'), ('VAL11'), ('VAL111')
--SELECT * FROM MASTER1
CREATE TABLE MASTER2 (MASTER2_UID INT IDENTITY(1,1) PRIMARY KEY, MASTER2_VAL VARCHAR(10))
INSERT INTO MASTER2 (MASTER2_VAL) VALUES ('VAL2'), ('VAL22'), ('VAL222')
--SELECT * FROM MASTER2
Now, I have a audit table like below,
CREATE TABLE AUDIT(BOOK_ID INT, FIELD_NAME VARCHAR(10), OLD_VAL VARCHAR(10), NEW_VAL VARCHAR(10))
INSERT INTO AUDIT VALUES (10, 'FIELD1', 'TEST-1', 'TEST-2'), (10, 'FIELD2', '1', '2'), (10, 'FIELD3', '1', '2')
--SELECT * FROM AUDIT
Here,
1. "FIELD2" data (1 & 2) linked with "MASTER1" table
2. "FIELD3" data (1 & 2) linked with "MASTER2" table
Now, I need to query on "AUDIT" table JOIN with master tables "MASTER1" & "MASTER2"and need below output,
Note - I having 15 master table and data in audit table with relation with those master tables.
Please suggest some query on this? Thanks!
 

Answer 1

CREATE TABLE MASTER1 (MASTER1_UID INT IDENTITY(1,1) PRIMARY KEY, MASTER1_VAL VARCHAR(10))
INSERT INTO MASTER1 (MASTER1_VAL) VALUES ('VAL1'), ('VAL11'), ('VAL111')
--SELECT * FROM MASTER1
CREATE TABLE MASTER2 (MASTER2_UID INT IDENTITY(1,1) PRIMARY KEY, MASTER2_VAL VARCHAR(10))
INSERT INTO MASTER2 (MASTER2_VAL) VALUES ('VAL2'), ('VAL22'), ('VAL222')
--SELECT * FROM MASTER2
CREATE TABLE AUDIT(BOOK_ID INT, FIELD_NAME VARCHAR(10), OLD_VAL VARCHAR(10), NEW_VAL VARCHAR(10))
INSERT INTO AUDIT VALUES (10, 'FIELD1', 'TEST-1', 'TEST-2'), (10, 'FIELD2', '1', '2'), (10, 'FIELD3', '1', '2')
--SELECT * FROM AUDIT
--select * from MASTER1
--select * from MASTER2
;with mycte as (
select * from Audit
cross apply (values(Cast(Old_Val as varchar(50))),(Cast(New_Val as varchar(50)))) d(val)
,mycte1 as (
Select BOOK_ID,FIELD_NAME, val, MASTER1_VAL, MASTER2_VAL
, row_number() Over(Partition by FIELD_NAME Order by val ) rn from mycte m0
Left join Master1 m1 on m0.val=Cast(m1.MASTER1_UID as varchar(50)) and m0.Field_NAME='FIELD2'
Left join Master2 m2 on m0.val=Cast(m2.MASTER2_UID as varchar(50) ) and m0.Field_NAME='FIELD3'
Select BOOK_ID, FIELD_NAME, [1] as OLD_VAL,[2] as NEW_VAL from
(Select BOOK_ID,FIELD_NAME, rn,coalesce(MASTER2_VAL, MASTER1_VAL, val) as val from mycte1) src
pivot (max(val) For rn in ([1],[2],[3])) pvt
drop table MASTER1,MASTER2,AUDIT