MySQL AUTO INCREMENT with Prefix (YYMM) that reset every month - mysql

Question

I saw another post explaining the use of sequence table to create prefixed AUTO INCREMENT ID.
Link to referenced post
SQL Fiddle
http://sqlfiddle.com/#!2/0ed88/1
I need the generated auto increment format to be: YYMM + AUTO INCREMENT VALUE that reset every month. For example now is January, 2015. The generated id should be: 15011, 15012, 15013, etc. Next month February 2015, the generated id should be: 15021, 15022, 15023, etc. I can use the above method to generate the prefix, however how do I reset the AUTO INCREMENT value each month? Database is InnoDB. Any help will be greatly appreciated :)
MODIFIED CODE
CREATE TABLE table1_seq
(
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
)|
CREATE TABLE Table1
(
id VARCHAR(7) NOT NULL PRIMARY KEY DEFAULT '0', name VARCHAR(30)
)|
CREATE TRIGGER tg_table1_insert
BEFORE INSERT ON table1
FOR EACH ROW
BEGIN
INSERT INTO table1_seq VALUES (NULL);
SET NEW.id = CONCAT(DATE_FORMAT(NOW(),'%y%m'), LAST_INSERT_ID());
END |
INSERT INTO Table1 (name) VALUES ('Jhon'), ('Mark')|

Answer 1

If you have a field DATE or DATETIME in your table then this solution maybe can help you.
Let say your table name my_table and has PK id (INT) and also a field bila (DATE). I just need to get last (biggest) id in current month from my_table then add by 1.
SET #mos= (SELECT MAX(id) FROM my_table WHERE MONTH(`bila`) = MONTH(NOW()) AND YEAR(`bila`) = YEAR(NOW()));
SET #mos = IF(
#mos IS NULL,
CONCAT(YEAR(NOW()),MONTH(NOW()),'001'),
#mos + 1
);
Then u can use #mos in your query next

Answer 2

To reset the AUTO_INCREMENT value, drop and recreate the table1_seq table. Given your example, a TRUNCATE statement would be sufficient (given that there aren't any foreign keys, and we assume the table is using either the MyISAM or InnoDB engine).
TRUNCATE TABLE table1_seq ;
(MySQL behavior for this statement is to create a new, empty table, with the AUTO_INCREMENT set back to the value when the table was created.)
This effectively achieves the same result as a DROP table followed by CREATE table.
That answers the question you asked. As a side note, generating a key value this way usually turns out to be a bad idea.

Answer 3

i've relied on the last answer above, i've used the orderDate field from my table and compared it with the current date during insertion , to decide finally if i want to reset or increment the purchaseOrderRef field:
The aim is to insert custom auto increment order id (field name: "purchaseOrderRef" ) with the format DD-MM-XXX in table [Products_SumOrders]. such that it resets the XXX to 0 automatically every month:
USE [Mydatabase] -- here you need to use your own database
GO
/****** Object: Trigger [dbo].[customAutoIncrement] Script Date: 10/1/2016 10:07:41 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER [dbo].[customAutoIncrement]
ON [dbo].[Products_SumOrders]
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON;
declare #maxOrderID int;
declare #maxOrderRef nvarchar(max);
declare #relativeID varchar(max);
declare #orderId int;
select #orderId =orderid from inserted;
print(#orderId);--allow me to display the inserted order id
SET #maxOrderID = (SELECT Max(orderid) FROM [Products_SumOrders] WHERE MONTH([OrderDate]) = (MONTH(GETDATE())) AND YEAR([OrderDate]) = YEAR(GETDATE()) and orderid < #orderId );
print(#maxOrderID);--last added order
--custom month format (always MM):
declare #mon int;
declare #stringMon nvarchar(10);
set #mon= MONTH(GETDATE());
IF #mon <10
set #stringMon ='0' + CONVERT(VARCHAR(1),#mon) ;
ELSE
set #stringMon = CONVERT(VARCHAR(2),#mon) ;
IF #maxOrderID is null --no orders has been added in this month:
begin
set #maxOrderRef = Substring(CONVERT(VARCHAR(4),YEAR(GETDATE())),3,4)+ '-'+ CONVERT(VARCHAR(2),#stringMon)+'-001';
end
ELSE
--custom order id format (always XXX):
begin
set #relativeID =(SELECT [purchaseOrderRef] FROM [Products_SumOrders] WHERE orderid=#maxOrderID);
set #relativeID = Substring(#relativeID,LEN(#relativeID)-(Charindex('-', REVERSE(#relativeID))-2),LEN(#relativeID));
print(CONVERT(int,#relativeID));
IF CONVERT(int,#relativeID) < 9
set #relativeID ='00' + CONVERT(VARCHAR(2),#relativeID+1) ;
ELSE
begin
if CONVERT(int,#relativeID) < 99
set #relativeID ='0' + CONVERT(VARCHAR(3),#relativeID+1) ;
else
set #relativeID = CONVERT(VARCHAR(3),#relativeID+1) ;
end
set #maxOrderRef = Substring(CONVERT(VARCHAR(4),YEAR(GETDATE())),3,4)+ '-'+ CONVERT(VARCHAR(2),#stringMon)+'-'+ CONVERT(VARCHAR(3),#relativeID);
end
print(#maxOrderRef);
UPDATE Products_SumOrders
SET purchaseOrderRef = #maxOrderRef
FROM inserted INNER JOIN [Products_SumOrders] On inserted.orderid = [Products_SumOrders].orderid
END
GO