Implement ROW_NUMBER() for mysql, maria if this window functions does not exists

row-number.sql

### http://www.mysqltutorial.org/mysql-row_number/

# simple row number

set @row_number = 0;
select (@row_number := @row_number + 1) AS num, id
FROM Term;

# select row number for each group  -----------------------------

set @row_number = 0;
set @year = null;
select 
  @row_number:=CASE
    WHEN @year = vsYear THEN @row_number + 1
    ELSE 1
  END AS num,
  @year := vsYear as vsYear,
  id, dateFrom, courseId
FROM Term
WHERE vsYear <> 16
order by vsYear, dateFrom

# update -----------------------------------------

set @row_number = 0;
set @year = null;
update Term
  set vsTerm = @row_number:=CASE
    WHEN @year = vsYear THEN @row_number + 1
    ELSE 1
  END,
  vsYear = @year := vsYear
WHERE vsYear <> 16
order by vsYear, dateFrom;