T-SQL compte les éléments en ajoutant et en supprimant

Question

Dans SQL Server 2008, j'ai Table1 et je veux obtenir la sortie comme indiqué dans la sortie attendue. À chaque fois que l'action «Compte» se produit, elle ajoute/supprime tous les éléments pertinents et affiche le total. En supposant que tous les éléments commencent par 0 compte.

Merci beaucoup.

CREATE TABLE Table1([Time] [smalldatetime] NULL,[Action] [nvarchar](10) NULL,[Item] [nchar](50) NULL) 
insert into Table1 values('2009-08-22 20:34:02','Count','Apple') 
insert into Table1 values('2009-08-22 20:34:03','Count','Banana') 
insert into Table1 values('2009-08-22 20:34:04','Count','Mango') 
insert into Table1 values('2009-08-22 20:34:05','Count','Black Berry') 
insert into Table1 values('2009-08-22 20:34:06','Count','Orange') 
insert into Table1 values('2009-08-22 20:34:07','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:08','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:09','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:10','Remove','Banana') 
insert into Table1 values('2009-08-22 20:34:11','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:12','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:13','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:14','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:15','Remove','Mango') 
insert into Table1 values('2009-08-22 20:34:17','Count','Apple') 
insert into Table1 values('2009-08-22 20:34:18','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:19','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:20','Remove','Banana') 
insert into Table1 values('2009-08-22 20:34:21','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:22','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:23','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:24','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:25','Remove','Apple') 
insert into Table1 values('2009-08-22 20:34:26','Count','Mango') 
insert into Table1 values('2009-08-22 20:34:27','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:28','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:29','Remove','Apple') 
insert into Table1 values('2009-08-22 20:34:30','Remove','Banana') 
insert into Table1 values('2009-08-22 20:34:31','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:32','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:33','Count','Banana') 
insert into Table1 values('2009-08-22 20:34:34','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:35','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:36','Remove','Mango') 
insert into Table1 values('2009-08-22 20:34:37','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:38','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:39','Count','Apple') 
insert into Table1 values('2009-08-22 20:34:40','Remove','Apple') 
insert into Table1 values('2009-08-22 20:34:41','Remove','Banana') 
insert into Table1 values('2009-08-22 20:34:42','Add','Banana') 
insert into Table1 values('2009-08-22 20:34:43','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:44','Count','Banana') 
insert into Table1 values('2009-08-22 20:34:45','Remove','Banana') 
insert into Table1 values('2009-08-22 20:34:46','Remove','Apple') 
insert into Table1 values('2009-08-22 20:34:47','Remove','Mango') 
insert into Table1 values('2009-08-22 20:34:48','Add','Apple') 
insert into Table1 values('2009-08-22 20:34:49','Add','Mango') 
insert into Table1 values('2009-08-22 20:34:50','Count','Mango') 

Answer 1

Ceci peut être réalisé avec une auto jointure externe gauche comme indiqué ci-dessous Cependant, les résultats obtenus sont différents de ce que vous avez montré probablement parce que vous avez fait des erreurs de calcul. Quoi qu'il en soit, essayez une approche similaire.

select a.time,a.item, 
SUM(case 
when b.action='Add' then 1 
when b.action='Remove' then -1 
else 0 end) 
from table1 as a 
left join table1 as b 
on a.item=b.item 
and b.time<a.time 
where a.action='Count' 
group by a.time,a.item,a.action 
order by 1