查詢太長，除了

Question

有沒有更簡單的方法...？

SELECT clid, cldoel, clanker, clprefix, clleerlijn, f1, f2, f3, f4 FROM Clusters 
WHERE clleerlijn like 'WJNLLUI%' AND (f3 IS NOT NULL OR f4 IS NOT NULL) 
AND clid in(
Select agClid FROM agenda2 as a JOIN evaluaties2 as e ON a.agclid = e.evalclid and agLkrid = evallkrid 
WHERE (agSchoolid='18' and agDatum >= '2013/01/01' and agDatum <= '2013/02/12') 
GROUP BY agClid 
except 
(SELECT agClid 
FROM agenda2 as a 
    JOIN evaluaties2 as e 
     ON a.agclid = e.evalclid and agLkrid = evallkrid 
WHERE agSchoolid='18' 
    and agLkrid in (1,2932,2935) 
    and agDatum >= '2013/01/01' 
    and agDatum <= '2013/02/12' 
    AND evalWaarde = 3 
GROUP BY agclid 
HAVING COUNT(DISTINCT agLkrid) = 3) 
) 

Answer 1

只有一點點短，但更好的可讀性，因爲同樣的CTE被使用了兩次：

WITH cte(clid) As (
    Select agClid FROM agenda2 as a JOIN evaluaties2 as e ON a.agclid = e.evalclid and agLkrid = evallkrid 
    WHERE (agSchoolid='18' and agDatum >= '2013/01/01' and agDatum <= '2013/02/12') 
) 
SELECT clid, cldoel, clanker, clprefix, clleerlijn, f1, f2, f3, f4 FROM Clusters 
WHERE clleerlijn like 'WJNLLUI%' AND (f3 IS NOT NULL OR f4 IS NOT NULL) 
AND clid in(
    SELECT DISTINCT agClid FROM cte 
    except 
    (SELECT agClid FROM cte WHERE agLkrid in (1,2932,2935) AND evalWaarde = 3 
    GROUP BY agclid 
    HAVING COUNT(DISTINCT agLkrid) = 3 
) 
) 

我也改變了第一GROUP BY的SELECT DISTINCT。

如果您正在尋找更高性能的解決方案，這將是沒有幫助的。重寫的SQL語句不會被更快地評估。