Dynamic SQL Joining between tables and Primary keys being configured within master tables

Question

Team , Thanks for your help in advance !
I'm looking out to code a dynamic SQL which should refer Master tables for table names and Primary keys and then Join for insertion into target tables .
EG:
INSERT INTO HUB.dbo.lp_order
SELECT *
FROM del.dbo.lp_order t1
where not exists ( select *
from hub.dbo.lp_order tw
where t1.order_id = t2.order_id )
SET @rows = @@ROWCOUNT
PRINT 'Table: lp_order; Inserted Records: '+ Cast(@rows AS VARCHAR)
-- Please note Databse names are going to remain the same but table names and join conditions on keys
-- should vary for each table(s) being configured in master tables
Sample of Master configuration tables with table info and PK Info :
Table Info         
Table_info_ID    Table_Name    
1        lp_order    
7        lp__transition_record    
Table_PK_Info        
Table_PK_Info_ID    Table_info_ID    PK_Column_Name
2                1    order_id
8                7    transition_record_id
There can be more than one join condition for each table
Thanks you !
Rajkumar Yelugu

Answer 1

Hi Rajkumar,
It is glad to hear that you figured the question out by yourself.
There's a flaw with your while loop in your sample code, just in case you hadn't noticed that, please see below.
--In this case, it goes to infinite loop
DECLARE @T TABLE(ID INT)
INSERT INTO @T VALUES(1),(3),(2)
DECLARE @ID INT
SELECT @ID = MIN(ID) FROM @T
WHILE @ID IS NOT NULL
PRINT @ID
SELECT @ID =ID FROM @T WHERE ID > @ID
So a cursor would be the appropriate option in your case, please reference below.
DECLARE @Table_Info TABLE
Table_info_ID INT,
Table_Name VARCHAR(99)
INSERT INTO @Table_Info VALUES(1,'lp_order'),(7,'lp__transition_record');
DECLARE @Table_PK_Info TABLE
Table_PK_Info_ID INT,
Table_info_ID INT,
PK_Column_Name VARCHAR(99)
INSERT INTO @Table_PK_Info VALUES(2,1,'order_id'),(8,7,'transition_record_id'),(3,1,'order_id2')
DECLARE @SQL NVarchar(MAX),
@ID INT,
@Table_Name VARCHAR(20),
@whereCondition VARCHAR(99)
DECLARE cur_Tabel_Info CURSOR
FOR SELECT Table_info_ID,Table_Name FROM @Table_Info
OPEN cur_Tabel_Info
FETCH NEXT FROM cur_Tabel_Info
INTO @ID, @Table_Name
WHILE @@FETCH_STATUS = 0
BEGIN
SELECT @whereCondition =ISNULL(@whereCondition+' AND ','') +'t1.'+PK_Column_Name+'='+'t2.'+PK_Column_Name FROM @Table_PK_Info WHERE Table_info_ID=@ID
SET @SQL = 'INSERT INTO hub.dbo.'+@Table_Name+'
SELECT * FROM del.dbo.'+@Table_Name+' AS T1
WHERE NOT EXISTS (
SELECT *
FROM hub.dbo.'+@Table_Name+' AS T2
WHERE '+@whereCondition+')'
SELECT @SQL
--EXEC(@SQL)
SET @whereCondition = NULL
FETCH NEXT FROM cur_Tabel_Info
INTO @ID, @Table_Name
END
Supposing you had noticed and fixed the flaw, your answer sharing is always welcome.
If you have any question, feel free to let me know.
Eric Zhang
TechNet Community Support