使用PHP和mysql有條件地對GROUP BY和COUNT進行多個

Question

首先，對於我的英語不好，我很抱歉，由於我使用手機並且我的代碼在我的辦公室PC上，所以沒有提供該代碼。 我一直在Google上搜索並嘗試使用UNION但結果與預期的不同。 請幫我解決這個問題。

我在mysql上有此訪問表：

| date              | merchant     | itemid |  act      | result |
|++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|
| 2015-07-19        | 3G Power     | 100    | visit     | OK     |
| 2015-07-19        | 3G Power     | 101    | visit     | OK     |
| 2015-07-19        | Anamely      | 200    | visit     | OK     |
| 2015-07-19        | Anamely      | 201    | visit     | OK     |
| 2015-07-19        | Anamely      | 202    | visit     | NOK    |
| 2015-07-19        | Anamely      | 203    | repair    | NOK    |
| 2015-07-20        | Garden Bay   | 300    | visit     | OK     |
| 2015-07-20        | Garden Bay   | 301    | install   | OK     |
| 2015-07-20        | Anamely      | 203    | repair    | OK     |

這是我嘗試過的UNION ：

create view allvisit (date, merchant, act, result, itemqty) as
select date, merchant, act, 'OK', count(itemid) from visit where result='OK' group by merchant
union
select date, merchant, act, 'NOK', count(itemid) from visit where result='NOK' group by merchant

我在html表中的預期結果是：

| date              | merchant     |  act      | result | itemqty |
|+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|
| 2015-07-19        | 3G Power     | visit     | OK      | 2      |
|                   | Anamely      | visit     | OK      | 2      |
|                   | Anamely      | visit     | NOK     | 1      |
|                   | Anamely      | repair    | NOK     | 1      |
| 2015-07-20        | Garden Bay   | visit     | OK      | 1      |
|                   | Garden Bay   | install   | OK      | 1      |
|                   | Anamely      | repair    | OK      | 1      |
|+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|
|     total work day.               | 2 days | tot qty| 9 items   |
|+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|

因此，條件是日期僅在每個相同日期的第一列和第一行上顯示，商家名稱對於每個act和結果僅顯示一次，並且使用count by itemid => itemqty count by itemid不只一個。 我希望有一個人可以幫助我。

Answer 1

我會試一試。 選擇狀態非常棘手，因此我使用了MAX函數。

select
  MIN(date),
  merchant,
  act,
  MAX(result),
  count(itemid) as itemqty
from MYTABLE 
GROUP BY merchant, act

Answer 2

我不知道該怎么解釋...我只是嘗試嘗試並從@beiller答案中編輯錯誤...

這是我預期結果的SQL工作：

create view allvisit (date, merchant, act, result, itemqty) as
select min(date) as date, merchant, act, 'OK', count(itemid) from visit where result='OK' group by merchant,act
union
select min(date) as date, merchant, act, 'NOK', count(itemid) from visit where result='NOK' group by merchant,act