Looping over the insert data into multiple tables - sql

Question

I have a query where I need to run to do manual inserts
I can do it but there are many records and was looking if I can build something.
I have a structure somewhat like this:
Have 4 id of a table - primary key values as:
var ids = "1,2,3,4";
loop over ids {
insert into table1(col1,col2,col3)
select col1,newid(),getdate() from table1 where id = ids - 1 at a time
var selectedID = get the id of the inserted row and then insert into anotehr table as:
insert into table2(col1,col2,col3,col4)
select selectedID, getdate(),getdate(),4 from table2 where fkID = ids - one at a time
}

Answer 1

You can use both loops and cursors but often they can be avoided.
Is there a specific reason you note you want them inserted one at a time? An alternative would be to have the IDs staged, in a temp table, or CTE, e.g.
;WITH [Ids] AS
(
SELECT '1' AS [ID]
UNION
SELECT '2'
UNION
SELECT '3'
UNION
SELECT '4'
)
INSERT INTO [Table1]
(
[Col1],
[Col2],
[Col3]
)
SELECT [Col1],
NEWID(),
GETDATE()
FROM [Table1] T
INNER JOIN [Ids] I ON I.[ID] = T.[Id];
Which avoids the need for any loops, and should perform much better.
Edit
The way I would structure this, to make the query reusable would be as follows:
IF OBJECT_ID('tempdb..#IDS') IS NOT NULL
BEGIN
DROP TABLE #IDS
END
IF OBJECT_ID('tempdb..#Inserted_IDS') IS NOT NULL
BEGIN
DROP TABLE #Inserted_IDS
END
CREATE TABLE #IDS
(
ID INT
);
CREATE TABLE #Inserted_IDS
(
ID INT,
);
INSERT INTO #IDS
(
ID
)
SELECT 1 UNION
SELECT 2 UNION
SELECT 3 UNION
SELECT 4;
INSERT INTO [Table1]
(
[Col1],
[Col2],
[Col3]
)
OUTPUT Inserted.ID
INTO #Inserted_IDS
SELECT [Col1],
NEWID(),
GETDATE()
FROM [Table1] T
INNER JOIN #IDS I ON I.[ID] = T.[Id];
INSERT INTO [table2]
(
[col1],
[col2],
[col3],
[col4]
)
SELECT I.[ID],
getdate(),
getdate(),
4
FROM [#Inserted_IDS] I
DROP TABLE #IDS;
DROP TABLE #Inserted_IDS;
Therefore you only need to amend the IDs being entered into the temp table each time you need to do the inserts.