MySQL - 總和表2列值顯示所有表1描述

Question

我對事務和類別分別具有以下表格。 我想寫一個查詢，將給我下面的查詢表中顯示的結果。

我曾嘗試以下

SELECT IFNULL(categories.Name,'Total') AS category, 
     IFNULL(SUM(transactions.Amount),0) AS amount, 
     categories.Color 
FROM transactions,categories 
WHERE categories.CatID = transactions.CatID 
GROUP BY categories.Name WITH ROLLUP 

但是，這是不是給我的B類，我想用零來顯示我的B類 - 0總如下。請幫助..

交易

+-----------+------------+------------+--------+ 
| TransID | SaleDate | CatID  | Amount | 
+-----------+------------+------------+--------+ 
|   1 | 2012-02-10 | 1   |  10 | 
|   2 | 2012-02-10 | 3   |  10 | 
|   3 | 2012-02-10 | 3   |  20 | 
|   4 | 2012-02-10 | 1   |  25 | 
|   5 | 2012-02-10 | 1   |  35 | 
|   6 | 2012-02-10 | 3   |  5 | 
|   7 | 2012-02-10 | 3   |  5 | 
+-----------+------------+------------+--------+ 

分類

+------------+------+----------+ 
| CatID  | Name | Color | 
+------------+------+----------+ 
|   1 | A | Green | 
|   2 | B | Red | 
|   3 | C | Blue | 
+------------+------+----------+ 

抵達結果下

+-----------+----------------+------------+ 
| Category | Amount  | Color  | 
+-----------+----------------+------------+ 
|   A | 70    | Green  | 
|   B | 40    | Blue  | 
|  Total | 110   | Blue  | 
+-----------+----------------+------------+ 

＃

所需的結果

+-----------+----------------+------------+ 
| Category | Amount  | Color  | 
+-----------+----------------+------------+ 
|   A | 70    | Green  | 
|   B | 0    | Red  | 
|   C | 40    | Blue  | 
|  Total | 110   | Pink  | 
+-----------+----------------+------------+ 

Answer 1

你正在尋找一個left join與rollup：

select coalesce(c.category, 'total') as category, 
     coalesce(sum(t.amount), 0) as amount, 
     coalesce(c.color, 'pink') as color -- this is weird 
from categories c left join 
    transactions t 
    on c.catid = t.catid 
group by c.category with rollup;