Compter et tabuler les enregistrements correspondants par mois

Question

Rookie a besoin d'un peu d'aide. Quelqu'un peut-il fournir une requête de compter facilement et puis par des enregistrements de tabuler mois correspondant à deux conditions pour éviter d'utiliser le code répétitif maladroit comme ça ...

SELECT 
SUM(CASE 
    WHEN extract(YEAR FROM `date`) = "2017" 
    AND extract(MONTH FROM `date`) = "07" 
    AND `conditionA` = "A" 
    AND `conditionB` = "B" 
    THEN 1 else 0 END) 
AS 2017_07 

SUM(CASE 
    WHEN extract(YEAR FROM `date`) = "2017" 
    AND extract(MONTH FROM `date`) = "08" 
    AND `conditionA` = "A" 
    AND `conditionB` = "B" 
    THEN 1 else 0 END) 
AS 2017_08 

SUM(CASE 
    WHEN extract(YEAR FROM `date`) = "2017" 
    AND extract(MONTH FROM `date`) = "09" 
    AND `conditionA` = "A" 
    AND `conditionB` = "B" 
    THEN 1 else 0 END) 
AS 2017_09 

FROM `datatable` 

Answer 1

Mettez les données en lignes, non colonnes:

SELECT extract(YEAR FROM `date`) as yyyy, extract(MONTH FROM `date`) as mm, 
     COUNT(*) 
FROM datatable 
WHERE `conditionA` = 'A' AND `conditionB` = 'B' 
GROUP BY extract(YEAR FROM `date`), extract(MONTH FROM `date`) 
ORDER BY yyyy, mm ;