如何優化查詢檢查表中多行的數據？

Question

基本上，我想從EXT表中的多行中檢索數據。

Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Charge code' and ITEM_PARAM_ATTR_VALUE='WDATRM') 
INTERSECT 
Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Charge code' and ITEM_PARAM_ATTR_VALUE='WDA4RM') 
INTERSECT 
Select package_id from EXT WHERE Priority > 299 
INTERSECT 
Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Rate table rate' and ITEM_PARAM_ATTR_VALUE='0.00000953') 
INTERSECT 
Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Usage category group' and ITEM_PARAM_ATTR_VALUE='H'); 

Answer 1

除非我錯了，它看起來喜歡，因爲所有的選擇所對同一個表，這個：

Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Charge code' and ITEM_PARAM_ATTR_VALUE='WDATRM') 
INTERSECT 
Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Charge code' and ITEM_PARAM_ATTR_VALUE='WDA4RM') 
INTERSECT 
Select package_id from EXT WHERE Priority > 299 

產生同樣的結果，因爲這：

Select package_id from EXT WHERE 
(ITEM_PARAM_ATTR_NAME='Charge code' and ITEM_PARAM_ATTR_VALUE='WDATRM') 
AND 
(ITEM_PARAM_ATTR_NAME='Charge code' and ITEM_PARAM_ATTR_VALUE='WDA4RM') 
AND 
(Priority > 299) 

第二方法更具可讀性，我懷疑它的執行速度也會更快。

Answer 2

我不知道是否會更快，但你可以給一個JOIN基礎的方法了一槍

SELECT CON1.package_id 
    FROM (SELECT DISTINCT package_id 
      FROM EXT 
     WHERE ITEM_PARAM_ATTR_NAME = 'Charge code' 
      AND ITEM_PARAM_ATTR_VALUE = 'WDATRM' 
     ) CON1 
INNER 
    JOIN (SELECT DISTINCT package_id 
      FROM EXT 
     WHERE ITEM_PARAM_ATTR_NAME = 'Charge code' 
      AND ITEM_PARAM_ATTR_VALUE = 'WDA4RM' 
     ) CON2 
    ON CON1.package_id = CON2.package_id 
INNER 
    JOIN (SELECT DISTINCT package_id 
      FROM EXT 
     WHERE Priority > 299 
     ) CON3 
    ON CON1.package_id = CON3.package_id  
INNER 
    JOIN (SELECT DISTINCT package_id 
      FROM EXT 
     WHERE ITEM_PARAM_ATTR_NAME = 'Rate table rate' 
      AND ITEM_PARAM_ATTR_VALUE = '0.00000953' 
     ) CON4 
    ON CON1.package_id = CON4.package_id  
INNER 
    JOIN (SELECT DISTINCT package_id 
      FROM EXT 
     WHERE ITEM_PARAM_ATTR_NAME = 'Usage category group' 
      AND ITEM_PARAM_ATTR_VALUE = 'H' 
     ) CON5 
    ON CON1.package_id = CON5.package_id  

編輯：那第一個沒有工作。 INTERSECTS可能會像它一樣好。如果這個更好，我會感到驚訝，但也許。

SELECT DISTINCT package_id 
    FROM (SELECT MAX(CASE WHEN ITEM_PARAM_ATTR_NAME = 'Charge code' 
         AND ITEM_PARAM_ATTR_VALUE = 'WDATRM' THEN 1 
         ELSE 0 
       ) OVER 
       (PARTITION BY package_id) CON1, 
       MAX(CASE WHEN ITEM_PARAM_ATTR_NAME = 'Charge code' 
         AND ITEM_PARAM_ATTR_VALUE = 'WDA4RM' THEN 1 
         ELSE 0 
       ) OVER 
       (PARTITION BY package_id) CON2, 
       MAX(CASE WHEN Priority > 299 THEN 1 
         ELSE 0 
       ) OVER 
       (PARTITION BY package_id) CON3, 
       MAX(CASE WHEN ITEM_PARAM_ATTR_NAME = 'Rate table rate' 
         AND ITEM_PARAM_ATTR_VALUE = '0.00000953' THEN 1 
         ELSE 0 
       ) OVER 
       (PARTITION BY package_id) CON4, 
       MAX(CASE WHEN ITEM_PARAM_ATTR_NAME = 'Usage category group' 
         AND ITEM_PARAM_ATTR_VALUE = 'H' THEN 1 
         ELSE 0 
       ) OVER 
       (PARTITION BY package_id) CON5, 
       CON1 + CON2 + CON3 + CON4 + CON5 AS ALLCON 
      FROM EXT  
     ) TMP 
WHERE ALLCON = 5; 

Answer 3

SELECT DISTINCT (package_id) 
    FROM EXT 
WHERE Item_param_attr_name = 'Usage category group' 
    AND Item_param_attr_value = 'H' 
    AND package_id IN 
     (SELECT DISTINCT (package_id) 
      FROM EXT 
     WHERE Item_param_attr_name = 'Charge code' 
      AND Item_param_attr_value = 'WDATRM' 
      AND Priority > 299 
      AND package_id IN 
       (SELECT DISTINCT (package_id) 
        FROM EXT 
       WHERE Item_param_attr_name = 'Charge code' 
        AND Item_param_attr_value = 'WDA4RM' 
        AND package_id IN 
         (SELECT DISTINCT (package_id) 
          FROM EXT 
         WHERE ITEM_PARAM_ATTR_NAME = 'Rate table rate' 
          AND ITEM_PARAM_ATTR_VALUE = '0.00000953')));