Sammenlign flere datointervaller

Efter afklaring i kommentar.

Din opgave, som jeg forstår den:

Tjek for alle leverede individuelle datointervaller (filter ) om de er omfattet af den kombinerede datointervaller for sæt koder i din tabel (invoice ).

Det kan gøres med almindelig SQL, men det er ikke en triviel opgave . Trinene kunne være:

1. Angiv datointervaller som filtre.

2. Kombiner datointervaller i invoice tabel pr. kode. Kan resultere i et eller flere intervaller pr. kode.

3. Se efter overlapninger mellem filtre og kombinerede fakturaer

4. Klassificer:fuldt dækket / delvist dækket. Kan resultere i en fuld dækning, en eller to delvise dækninger eller ingen dækning. Reducer til maksimalt dækningsniveau.

5. Vis en række for hver kombination af (filter, kode) med den resulterende dækning i en fornuftig sorteringsrækkefølge

Ad hoc-filterintervaller

WITH filter(filter_id, startdate, enddate) AS (
    VALUES
      (1, '2012-05-01'::date, '2012-06-05'::date) -- list filters here.
     ,(2, '2012-05-01', '2012-05-31')
     ,(3, '2012-06-01', '2012-06-30')
    )
SELECT * FROM filter;

Eller læg dem i en (midlertidig) tabel og brug tabellen i stedet.

Kombiner overlappende/tilstødende datointervaller pr. kode

WITH a AS (
    SELECT code, startdate, enddate
          ,max(enddate) OVER (PARTITION BY code ORDER BY startdate) AS max_end
-- Calculate the cumulative maximum end of the ranges sorted by start
    FROM   invoice
    ), b AS (
    SELECT *
          ,CASE WHEN lag(max_end) OVER (PARTITION BY code
                                        ORDER BY startdate) + 2 > startdate
-- Compare to the cumulative maximum end of the last row.
-- Only if there is a gap, start a new group. Therefore the + 2.
           THEN 0 ELSE 1 END AS step
    FROM   a
    ), c AS (
    SELECT code, startdate, enddate, max_end
          ,sum(step) OVER (PARTITION BY code ORDER BY startdate) AS grp
-- Members of the same date range end up in the same grp
-- If there is a gap, the grp number is incremented one step
    FROM   b
    )
SELECT code, grp
      ,min(startdate) AS startdate
      ,max(enddate) AS enddate
FROM   c
GROUP  BY 1, 2
ORDER  BY 1, 2

Alternativ endelig SELECT (kan være hurtigere eller ej, du bliver nødt til at teste):

SELECT DISTINCT code, grp
          ,first_value(startdate) OVER w AS startdate
          ,last_value(enddate) OVER w AS enddate
FROM   c
WINDOW W AS (PARTITION BY code, grp ORDER BY startdate
             RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) 
ORDER  BY 1, 2;

Kombiner til én forespørgsel

WITH 
    -- supply one or more filter values
    filter(filter_id, startdate, enddate) AS (
    VALUES
      (1, '2012-05-01'::date, '2012-06-05'::date) -- cast values in first row
     ,(2, '2012-05-01', '2012-05-31')
     ,(3, '2012-06-01', '2012-06-30')
    )
    -- combine date ranges per code
    ,a AS (
    SELECT code, startdate, enddate
          ,max(enddate) OVER (PARTITION BY code ORDER BY startdate) AS max_end
    FROM   invoice
    ), b AS (
    SELECT *
          ,CASE WHEN (lag(max_end) OVER (PARTITION BY code ORDER BY startdate)
                      + 2) > startdate THEN 0 ELSE 1 END AS step
    FROM   a
    ), c AS (
    SELECT code, startdate, enddate, max_end
          ,sum(step) OVER (PARTITION BY code ORDER BY startdate) AS grp
    FROM   b
    ), i AS ( -- substitutes original invoice table
    SELECT code, grp
          ,min(startdate) AS startdate
          ,max(enddate) AS enddate
    FROM   c
    GROUP  BY 1, 2
    )
    -- match filters
    , x AS (
    SELECT f.filter_id, i.code
            ,bool_or(f.startdate >= i.startdate
              AND f.enddate   <= i.enddate) AS full_cover
    FROM   filter f
    JOIN   i ON i.enddate >= f.startdate
            AND i.startdate <= f.enddate -- only overlapping
    GROUP  BY 1,2
    )
SELECT f.*, i.code
      ,CASE x.full_cover
        WHEN TRUE  THEN 'fully covered'
        WHEN FALSE THEN 'partially covered'
        ELSE            'invoice missing'
       END AS covered
FROM   (SELECT DISTINCT code FROM i) i
CROSS  JOIN filter f -- all combinations of filter and code
LEFT   JOIN x USING (filter_id, code)    -- join in overlapping
ORDER  BY filter_id, code;

Testet og virker for mig på PostgreSQL 9.1.