MSSQL auto-increment ID with Prefix - sql

Question

I want to achieve an auto increment ID with prefix but resetting the number if it has different prefix.
The output I want looks like this:
ID PREFIX PROJECTID
1 PID_ PID_1
2 PID_ PID_2
3 RID_ RID_1
4 RID_ RID_2
But the result I got with my script is this:
ID PREFIX PROJECTID
1 PID_ PID_1
2 PID_ PID_2
3 RID_ RID_3
4 RID_ RID_4
Here's my script to create the table
CREATE TABLE PROJECTS
(ID INT IDENTITY(1,1) NOT NULL,
PREFIX NVARCHAR(10) NOT NULL,
PROJECTID AS ISNULL(PREFIX + CAST(ID AS NVARCHAR(10)), '') PERSISTED)
INSERT INTO PROJECTS(PREFIX) VALUES('PID_'),('PID_'),('RID_'),('RID_')
I'm using MS SQL 2012

Answer 1

you want like this
CREATE TABLE #PROJECTS
(
ID INT IDENTITY(1, 1)
NOT NULL ,
PREFIX NVARCHAR(10) NOT NULL ,
PROJECTID NVARCHAR(11)
)
INSERT INTO #PROJECTS
( PREFIX )
VALUES ( 'PID_' ),
( 'PID_' ),
( 'RID_' ),
( 'RID_' )
suppose you have above data in your table
now if you want to perform insert with DECLARE #PREFIX NVARCHAR(10) = 'RID_'
INSERT INTO #PROJECTS
( PREFIX ,
PROJECTID
)
SELECT #PREFIX ,
#PREFIX + CAST(( COUNT(TT.rn) + 1 ) AS NVARCHAR(1))
FROM ( SELECT ROW_NUMBER() OVER ( PARTITION BY P.PREFIX ORDER BY ( SELECT
NULL
) ) AS rn
FROM #PROJECTS AS P
WHERE P.PREFIX = #PREFIX
) AS tt
see above query may helps you.

Answer 2

Hi i found the ansowr after working couple of hours in Ms Sql server
USE [StocksDB]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER TRIGGER [dbo].[tb1_triger]
ON [dbo].[Table1]
instead of INSERT
AS
declare #name nchar(12)
select top 1 #name=name from inserted
declare #maxid char(12)
select #maxid = MAX(id1) from Table1
BEGIN
SET NOCOUNT ON;
if (#maxid is null)
begin
set #maxid=0
end
set #maxid= substring(#maxid, 5 , LEN(#maxid))+1
INSERT INTO table1
(id1,name) SELECT CONCAT_WS((REPLICATE('0',12-4-LEN(#maxid))),'tblo',#maxid),i.name
from inserted i
END

Answer 3

You can do this with an INSTEAD OF trigger on the table rather than using a PERSISTED column. I have written the trigger so that it will correctly handle bulk inserts as this is something many people overlook. Also, for my solution it is not necessary to have an IDENTITY column on the table if you do not want it.
So the table has been defined with the column included. Also, you can get rid of the IDENTITY column as I mentioned above:
CREATE TABLE dbo.PROJECTS
(
ID INT IDENTITY(1, 1) NOT NULL,
PREFIX NVARCHAR(10) NOT NULL,
PROJECTID NVARCHAR(20) NOT NULL
);
One note - since the PREFIX column is NVARCHAR(10) and I do not know how big the numbers will get, the size of the PROEJCTID column was increased to prevent overflow. Adjust the size as your data requires.
Here is the trigger:
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER dbo.InsertProjects
ON dbo.PROJECTS
INSTEAD OF INSERT
AS
BEGIN
SET NOCOUNT ON;
DECLARE #rowsAffected INT = (SELECT COUNT(*) FROM Inserted);
-- if there are no rows affected, no need to do anything
IF #rowsAffected = 0 RETURN;
DECLARE #ExistingCounts TABLE (
Prefix NVARCHAR(10) NOT NULL,
ExistingCount INT NOT NULL
);
-- get the count for each existing prefix
INSERT INTO #ExistingCounts(Prefix, ExistingCount)
SELECT PREFIX, COUNT(*) FROM dbo.PROJECTS GROUP BY PREFIX;
-- since this is an INSTEAD OF trigger, we must do the insert ourself.
-- a prefix might not exist, so use ISNULL() to get a zero in that case.
INSERT INTO dbo.PROJECTS
(
PREFIX, PROJECTID
)
SELECT sub.PREFIX,
-- the number after the prefix is the existing count for the prefix plus
-- the position of the prefix in the Inserted table
sub.PREFIX + CAST((sub.ExistingCount + sub.Number) AS NVARCHAR(10))
FROM
(SELECT i.PREFIX,
-- get the position (1, 2, 3...) of the prefix in the Inserted table
ROW_NUMBER() OVER(PARTITION BY i.PREFIX ORDER BY i.PREFIX) AS [Number],
-- get the existing count of the prefix
ISNULL(c.ExistingCount, 0) AS [ExistingCount]
FROM Inserted AS i
LEFT OUTER JOIN #ExistingCounts AS c ON c.Prefix = i.PREFIX) AS sub;
END
GO
I have included comments in the source code to explain the simple logic. Hopefully this helps and is what you are looking for :-)

Answer 4

Hey use this query..
CREATE FUNCTION DBO.GET_NEX_P_ID(#PREF VARCHAR(4))
RETURNS NVARCHAR(24)
AS
BEGIN
RETURN (SELECT #PREF+CAST(COUNT(1)+1 AS VARCHAR) FROM PROJECTS WHERE PREFIX=#PREF)
END
GO
CREATE TABLE PROJECTS
(
PREFIX VARCHAR(8),
PROJECTID NVARCHAR(24)
)
GO
INSERT INTO PROJECTS
VALUES('PRJ_',DBO.GET_NEX_P_ID('PRJ_'))
GO
INSERT INTO PROJECTS
VALUES('PRQ_',DBO.GET_NEX_P_ID('PRQ_'))
GO
Thanks