Insert into Multiple Related Tables Using INSERT_IDENTITY in SQL Server

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Okay setting the scene. I have three tables, (Table1, Table2 and DataTable) and I want to insert into Table1 and Table2 using DataTable as source.
So for every row in DataTable I want a row in Table1 and Table2, and Table2 needs to have the inserted id (PK) from Table1…

If I were to do this…

INSERT INTO Table1 SELECT A, B, C FROM MyTable
INSERT INTO Table2 SELECT IDENTITY_INSERT(), D, E, F FROM MyTable

I'd get the ID of the last inserted record into Table1.

Is a CURSOR or WHILE loop the only ways to do this?

Best Answer

A solution that might work for you is using the OUTPUT clause, which spits out all the inserted rows, so you can re-insert them into a different table. However, this puts limitations on foreign key constraints on Table2, if memory serves.

Anyway, the solution would look something like this:

MERGE INTO Table1 AS t1
USING MyTable ON 1=0 -- always generates "not matched by target"

WHEN NOT MATCHED BY TARGET THEN
    -- INSERT into Table1:
    INSERT (A, B, C) VALUES (t1.A, t1.B, t1.C)

--- .. and INSERT into Table2:
OUTPUT inserted.ID, MyTable.D, MyTable.E, MyTable.F
INTO Table2 (ID, D, E, F);

MERGE, as opposed to the other DML statements, can reference other tables than just inserted and deleted, which is useful for you here.

More: http://sqlsunday.com/2013/08/04/cool-merge-features/

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MySQL Insert into two tables using new IDs

After your query runs, you'll have a set of copied rows (with configid=41) and an identical set of pasted rows (except for the configid=76 and the auto-created id).

Since, these ids are not known in advance, you'll need another way to identify rows of the config table, e.g. a unique key (besides the auto-incrementing one), so you can match (join) the newly created rows with the old ones.

If, for example, the (configid, optionname) is unique, then the following would work:

INSERT INTO pricing
    ( relid, price, ... )          --- relid and all the other columns, 
                                   --- except any autoincrement you may have
SELECT pasted.id, p.price, ....    --- and the same columns here
FROM 
    pricing AS p
  JOIN
    tblproductconfigoptionssub AS copied
      ON  copied.id = p.relid
      AND copied.configid = 41 
  JOIN
    tblproductconfigoptionssub AS pasted
      ON  pasted.optioname = copied.optioname
      AND pasted.configid = 76 ;

Sql-server – Combine – Select Into, with Insert Into Select

When the automation fires off the second time, I get an error because the table already exists and, consequently, the second round of data isn't inserted.

I would suggest you to put a condition to check the existence of the table

If exists (select 1 from sys.tables where name = '' and type = 'U')
begin -- table exists, so insert values in it
insert into table_name values ()
end
else
begin -- table does not exist, so create it
create table table_name (column datatype)
insert into table_name values ()
end

You can even use below sql to create new blank table as the where 1=0 will always be false.

Note that it wont create any indexes from old_table into new_table.

SELECT *
INTO new_table
FROM old_table where 1=0

To capture errors, you can use TRY/CATCH

Best Answer

Related Solutions

MySQL Insert into two tables using new IDs

Sql-server – Combine – Select Into, with Insert Into Select

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