Insert n rows stored procedure - sql

Question

Trying to insert multiple rows based on a passed parameter.
Tried this and it only repeated once:
ALTER PROCEDURE [dbo].[ActivateCertificates]
#Count int,
#CertificateNumber int,
#Buyer VarChar(50)
AS
Declare #x int
Declare #InitialCharacter Char(1)
SET #InitialCharacter='C'
Declare #Last3 Char(3)
SET #Last3='867'
while #x <= #Count
begin
/* CREATE THE CERTIFICATE NUMBER */
set #CertificateNumber = #CertificateNumber +1
/* insert into certificates cert number and who sold to. */
INSERT into Certificates (CertificateNumber,Buyer)
VALUES (#InitialCharacter + ltrim(rtrim(cast(#CertificateNumber as char))) + #Last3, #Buyer)
end
set #x =#x + 1
GO

Answer 1

Your variable is incremented outside the BEGIN/END block. Also I would recommend you initially set your variable to 0 to avoid any potential garbage data stored in that memory location.

Answer 2

To achieve your goal using a set-based query instead of a loop (BTW there are lots of such examples here on StackOverflow) you'll have to have a tally (numbers) table or create it on a fly with a subquery or recursive CTE.
CREATE TABLE tally (id INT NOT NULL PRIMARY KEY);
To populate it up to 100000 (Celko-style)
INSERT INTO tally (id)
SELECT a.N + b.N * 10 + c.N * 100 + d.N * 1000 + e.N * 10000 + 1 as N
FROM (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) a
, (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) b
, (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) c
, (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) d
, (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) e
ORDER BY N;
Now your stored procedure boils down to one statement
CREATE PROCEDURE ActivateCertificates
#Count INT,
#CertificateNumber INT,
#Buyer VARCHAR(50)
AS
INSERT INTO Certificates (CertificateNumber, Buyer)
SELECT 'C' + CAST(q.number + t.id AS VARCHAR(12)) + '867', q.buyer
FROM
(
SELECT #CertificateNumber number, #Buyer buyer
) q, tally t
WHERE t.id <= #Count;
Here is SQLFiddle demo
Now if you generate relatively small amounts of certificates (< 32768) then you can use recursive CTE to build a sequence of numbers (and don't need a persisted tally table)
CREATE PROCEDURE ActivateCertificates
#Count INT,
#CertificateNumber INT,
#Buyer VARCHAR(50)
AS
WITH tally AS (
SELECT 1 id
UNION ALL
SELECT id + 1 FROM tally WHERE id < #Count
)
INSERT INTO Certificates (CertificateNumber, Buyer)
SELECT 'C' + CAST(q.number + t.id AS VARCHAR(12)) + '867', q.buyer
FROM
(
SELECT #CertificateNumber number, #Buyer buyer
) q, tally t OPTION (MAXRECURSION 32767);
Here is SQLFiddle demo for that case