如何從另一個查詢結果MYSQL減去一個查詢結果

Question

1查詢

(SELECT a.cat_id, 
      a.cat_name, 
      a.cat_description, 
      b.subcat_name, 
      b.subcat_description 
    FROM trade_categories a 
LEFT JOIN trade_subcategories b ON a.cat_id = b.cat_id 
    WHERE a.cat_name LIKE '%catty%' 
     OR a.cat_description LIKE '%catty%') 
UNION 
    (SELECT c.cat_id, 
      d.cat_name, 
      d.cat_description, 
      c.subcat_name, 
      c.subcat_description 
    FROM trade_subcategories c 
LEFT JOIN trade_categories d ON c.cat_id = d.cat_id 
    WHERE c.subcat_name LIKE '%catty%' 
     OR c.subcat_description LIKE '%catty%') 

第二查詢：

SELECT x.cat_id, 
     x.cat_name, 
     x.cat_description, 
     y.subcat_name, 
     y.subcat_description 
FROM trade_categories x 
    JOIN trade_subcategories y ON x.cat_id = y.cat_id 
WHERE ( x.cat_name LIKE '%catty%' 
     OR x.cat_description LIKE '%catty%') 
    AND ( y.subcat_name NOT LIKE '%catty%' 
     OR y.subcat_description NOT LIKE '%catty%') 

我要減去1查詢結果中的第2個查詢結果。

Answer 1

http://www.bitbybit.dk/carsten/blog/?p=71

或 例如：

SELECT Name FROM employee1 WHERE name NOT IN (SELECT name FROM employee2); 

Answer 2

我認爲你可以做一個NOT IN或LEFT JOIN。我更喜歡LEFT JOIN。

因此，例如，

SELECT `QUERY_ONE`.* 
FROM `QUERY_ONE` 
LEFT JOIN `QUERY_TWO` USING (`cat_id`) 
WHERE QUERY_TWO.cat_id IS NULL; 

其中QUERY_ONE和QUERY_TWO是你的兩個查詢

Answer 3

SELECT a.cat_id, 
      a.cat_name, 
      a.cat_description, 
      b.subcat_name, 
      b.subcat_description 
    FROM trade_categories a 
LEFT JOIN trade_subcategories b ON a.cat_id = b.cat_id 
    WHERE a.cat_name NOT LIKE '%catty%' 
     AND a.cat_description NOT LIKE '%catty%' 
     AND (b.cat_id IS NULL 
     OR b.subcat_name NOT LIKE '%catty%' AND b.subcat_description NOT LIKE '%catty%') 

或別名，如果兩個查詢的結果已經被存儲在（臨時）表，你可以使用@Abhay的解決方案。