SQL / Coalesce - Wrong row name - mysql

Question

I have a problem with the request below!
REQUEST:
SELECT COALESCE(date(date_field), 'Total') AS "date_field_group",
COUNT( id_field ) AS "Nombre de bookings",
CONCAT( REPLACE( REPLACE( FORMAT( SUM( price1 ) , 2 ) , ',', ' ' ) , '.', ',' ) , ' €' ) AS "Total à l'achat",
CONCAT( REPLACE( REPLACE( FORMAT( SUM( price2 ) , 2 ) , ',', ' ' ) , '.', ',' ) , ' €' ) AS "Total à la vente",
CONCAT( REPLACE( REPLACE( FORMAT( SUM( price2 ) - SUM( price1 ) , 2 ) , ',', ' ' ) , '.', ',' ) , ' €' ) AS 'Marge',
CONCAT( REPLACE( FORMAT( (SUM( price2 ) / SUM( price1 ) ) , 2 ) , '1.', '' ) , ' ', '%') AS "Markup moyen"
FROM table1 S, table2 B
WHERE status_field
IN ( "1", "5")
AND DATE( date_field ) BETWEEN "2011-08-01" AND "2011-08-31"
AND type_field = "H"
AND price1 IS NOT NULL
AND S.id_field = B.id_field
AND B.id2 = "1"
GROUP BY date_field_group WITH ROLLUP
The thing is that the request is working fine (right numbers), but in the last line I was expected to get in first row "Total" and instead of that I got a field NULL...
Is someone know what is wrong with my request ?
Thx for any help ;).

Answer 1

You're query is almost correct (except for using implicit SQL '89 joins, which is an SQL anti-pattern)
The problem is in the last line: GROUP BY ... WITH ROLLUP.
The rollup gets applied very late in the process, after your COALESCE(date(date_field), 'Total').
So the coalesce has already finished by the time rollup comes along you need to rewrite the query like so:
SELECT COALESCE(date_field_group, 'Total') as date_field_group
, `Nombre de bookings`
, `Total à l'achat`
, `Total à la vente`
, `Marge`
, `Markup moyen`
FROM (
SELECT date(date_field) AS "date_field_group",
COUNT( id_field ) AS "Nombre de bookings",
CONCAT( REPLACE( REPLACE( FORMAT( SUM( price1 ) , 2 ) , ',', ' ' ) , '.', ',' ) , ' €' ) AS "Total à l'achat",
CONCAT( REPLACE( REPLACE( FORMAT( SUM( price2 ) , 2 ) , ',', ' ' ) , '.', ',' ) , ' €' ) AS "Total à la vente",
CONCAT( REPLACE( REPLACE( FORMAT( SUM( price2 ) - SUM( price1 ) , 2 ) , ',', ' ' ) , '.', ',' ) , ' €' ) AS 'Marge',
CONCAT( REPLACE( FORMAT( (SUM( price2 ) / SUM( price1 ) ) , 2 ) , '1.', '' ) , ' ', '%') AS "Markup moyen"
FROM table1 S
INNER JOIN table2 B ON (S.id_field = B.id_field)
WHERE status_field IN ( "1", "5")
AND DATE( date_field ) BETWEEN "2011-08-01" AND "2011-08-31"
AND type_field = "H"
AND price1 IS NOT NULL
AND B.id2 = "1"
GROUP BY date_field_group WITH ROLLUP ) AS subquery