Custom method to implement simple order numbers

Add the number of the last order 1 (12-digit big data type)Create Function gettime (-- Definition variable) returns char (12) -- return type asbegin -- function body declare @ num decimal; -- growth number declare @ ID char (12 ); -- Return Value -- query the number of orders in the order table for the current day. Select @ num = count (*) from DBO. dd where convert (varchar (8), DBO. DD. ddsj, 112) = convert (varchar (8), getdate (), 112); -- if the current number is, incremental Int = 0001 if (@ num <= 0) begin set @ num = @ num + 1; Set @ ID = convert (varchar (8), getdate (), 112) + '000' + convert (varchar (4 ), @ num); End else -- if it is not zero, add the number of the last order to prevent repeated orders from begin select top 1 @ num = Ddid from DD order by Ddid DESC after deletion; set @ num = @ num + 1; Set @ ID = convert (varchar (12), @ num); end return @ ID; end; go