mysql row number 28 29 example

1SELECT row_number() over ( order by firstName) RowNumberSqeuence,FirstName from rowNumberDemo
2 order by FirstName;

1
2        
3            
4        
5     set @row_number := 0;
6
7SELECT 
8    @row_number:=CASE
9        WHEN @customer_no = customerNumber 
10			THEN @row_number + 1
11        ELSE 1
12    END AS num,
13    @customer_no:=customerNumber customerNumber,
14    paymentDate,
15    amount
16FROM
17    payments
18ORDER BY customerNumber;

1SET @row_number = 0; 
2SELECT 
3    (@row_number:=@row_number + 1) AS num, 
4    firstName, 
5    lastName
6FROM
7    employees
8ORDER BY firstName, lastName    
9LIMIT 5;