nozzy

delete from links 
where id = (
  select min(id) 
  from links
  group by user_id
  having count(id) > 9
  and user_id = 222
);
insert into ..... ;

select countries.name, regions.name, cities.name, count(camps.id) from camps 
inner join countries on countries.id = camps.region_id
inner join regions on regions.id = camps.region_id
inner join cities on cities.id = camps.region_id
group by countries.name, regions.name, cities.name

Это полный писец, я лично в шоке.

select 
t1.name,
t2.d,
t2.value
from group t1
inner join
(
  select
  group_id,
  value,
  max(date) as d
  from stat
  group by group_id,  value
  ) t2 on t2.group_id = t1.id

Рекомендую качать отсюда:
dev.mysql.com/downloads
Скачать нужно MySQL Community Server и MySQL Workbench.
Во время инсталляции установить тестовые базы и вперед...

Если правильно понял:

select
usr.*,
recept.*
from 
(
	select distinct
	t2.*
	from tovary t1
	inner join recepty t2 	on t2.product_use_1 = t1.id
							or t2.product_use_2 = t1.id
							or t2.product_use_3 = t1.id
							// и тд до t2.product_use_9
      where t1.id = ####
) as recept
inner join 
(
	select
	t1.id,
	t1.name,
	t2.own_id
	from 
	users  t1
	inner join comments t2 on t1.id = t2.own_id
) as usr on usr.own_id = recept.own_id

select
t.'Display Name',
t.'Course',
t.'Category',
t.'Item Name',
MAX(CASE WHEN t.'idnumber' = 'a1' THEN t.'Grade' ELSE NULL END) AS 'оценка А',
MAX(CASE WHEN t.'idnumber' = 'b1' THEN t.'Grade' ELSE NULL END) AS 'оценка Б'
// и так далее:  c1,d1 и t1
from
( 
// ВАШ ЗАПРОС, добавил - gg.idnumber AS 'idnumber'
  SELECT u.firstname AS 'First' , u.lastname AS 'Last', u.firstname + ' ' + u.lastname AS            'Display Name',
  c.fullname AS 'Course', 
  cc.name AS 'Category',

  CASE 
  WHEN gi.itemtype = 'course' 
  THEN c.fullname + ' Course Total'
  ELSE gi.itemname
  END AS 'Item Name',

  ROUND(gg.finalgrade,2) AS Grade,

  gg.idnumber AS 'idnumber'

  FROM prefix_course AS c
  JOIN prefix_context AS ctx ON c.id = ctx.instanceid
  JOIN prefix_role_assignments AS ra ON ra.contextid = ctx.id
  JOIN prefix_user AS u ON u.id = ra.userid
  JOIN prefix_grade_grades AS gg ON gg.userid = u.id
  JOIN prefix_grade_items AS gi ON gi.id = gg.itemid
  JOIN prefix_course_categories AS cc ON cc.id = c.category

  WHERE gi.courseid = c.id 
  ORDER BY lastname
) t
group by t.'Display Name',
t.'Course',
t.'Category',
t.'Item Name'

БД с веб-интерфейсом:
October CMS (на Laravel) или
Bolt CMS (попроще)

update table as t1
inner join 
(
  select 
  keyword,
  count(*) as cnt
  from table
  group by keyword
) t2 on t2.keyword = t1.keyword
set t1.keyword = concat(t1.keyword, floor(rand() * 10000000)) 
where t2.cnt > 1

echo '<h2>Редактировать</h2>';
$query = 'SELECT * FROM lection WHERE id='.$_GET['id'];

Так редактировать очень плохо, злодеи могут вам отредактировать базу.

select 
t1.id,
t1.name,
ifnull(t2.count_table1_id, 0)
from table1 t1
left join (
	select 
	table1_id,
	count(*) as count_table1_id
	from table2
	group by table1_id
) t2 on t1.id = t2.table1_id

Используйте
select * from table for update;
update table ....;