Detailed ideas for implementing the order number and flow ticket number (8 bits) in the Stored Procedure

This article draws on the great gods in the garden and I just want to make some modifications. If there is something bad, please try again.
First write the Implementation ideas and then paste the code
1. Create a stored procedure, declare the output parameter @ indentNum, and output the order number.
2. Generally, the order number consists of two parts: the date and the subsequent order number. You can view the number of digits after the date based on your needs. This article is 8 digits.
3. Define the function @ date as the date part and assign values.
4. check whether there is data for the current day In the table. query by date. Generally, there is a date in the order table.
5. If the table exists, + 1 is added to the largest order in the table. If not, the First Order Number of the current day is added.
Note: Replicate, a function that is rarely used, is used, because when the maximum order is + 1, the high 0 must be added.
Syntax: Print replicate ('0', 3) ---- three zeros are output.
Copy codeThe Code is as follows:
USE MyBookShop
GO
-- Delete a stored procedure
IF OBJECT_ID ('proc _ NumIndent ') IS NOT NULL
Drop proc PROC_NumIndent
GO
-- Create a stored procedure for generating the flow ticket number
Create proc PROC_NumIndent
@ IndentNum nvarchar (20) output -- streamline number
AS
-- The date part is the current date.
DECLARE @ date nvarchar (20)
Set @ date = convert (varchar (20), getdate (), 112) -- format: 20130117
-- Determine whether the table contains data of the current day
DECLARE @ CountMax nvarchar (20)
Select @ CountMax = max (id) from testst where convert (varchar (10), rtrim (ltrim (date) = convert (varchar (10 ), rtrim (ltrim (getdate ())))
-- If @ CountMax is not equal to null, the table contains data of the current day.
IF (@ CountMax <> '')
BEGIN
Declare @ num nvarchar (20)
-- Convert the 8-digit rightmost (next) digits of the largest order obtained today to the int type plus one
Set @ num = convert (varchar (20), convert (int, right (@ CountMax, 8) + 1)
-- Use the replicate function to repeat the value of '0' to add a high position.
Set @ num = replicate ('0', 8-len (@ num) + @ num
Set @ indentNum = @ date + @ num
Print @ indentNum
END
-- If it does not exist, add '123' as the first order of the current day.
ELSE
BEGIN
Set @ indentNum = @ date + '123'
PRINT @ indentNum
END
GO
-- The following describes the stored procedure.
DECLARE @ indentNum nvarchar (20)
EXEC PROC_NumIndent @ indentNum

We also hope that you will be able to provide a better way to compare dates.
It is to judge whether two dates are equal, and the database uses the datatime format. However, it is quite painful to judge.
You also want to take the date part instead of the time part for determination. I hope you can talk about it more.