SQL Oracle Counting Clusters

Pomocí funkcí LEAD a LAG v ORACLE můžete vytvořit tyto dotazy:

1. Počet odstávek:

WITH IntTable AS
( SELECT * FROM
  (
   SELECT dt b_date,value,LEAD(dt) OVER (ORDER BY dt) e_date  FROM
     (
        select "Date" dt,"Value" value,
               LAG("Value") OVER (ORDER BY "Date") pvalue,
               LEAD("Value") OVER (ORDER BY "Date") nvalue
        from T
     ) T1
     WHERE pvalue is NULL or value<>pvalue or nvalue is NULL 
   )
WHERE E_DATE is NOT NULL
)
SELECT COUNT(*) FROM IntTable where value = 0 

Ukázka SQLFiddle

2. Období mezi každým vypnutím

WITH IntTable AS
( SELECT * FROM
  (
   SELECT dt b_date,value,LEAD(dt) OVER (ORDER BY dt) e_date  FROM
     (
        select "Date" dt,"Value" value,
               LAG("Value") OVER (ORDER BY "Date") pvalue,
               LEAD("Value") OVER (ORDER BY "Date") nvalue
        from T
     ) T1
     WHERE pvalue is NULL or value<>pvalue or nvalue is NULL 
   )
WHERE E_DATE is NOT NULL
)
SELECT b_date,e_date, (e_date-b_date) * 60 * 24 FROM IntTable where value = 1 

Ukázka SQLFiddle