合併2個查詢與不同的WHERE子句

Question

我有以下查詢：

select 
* 
from 
(
SELECT art_titel as at, COUNT(*) as Number1 
FROM artikel_views 
WHERE user_id != '' 
GROUP BY art_titel 
ORDER BY Number1 desc 
) as FirstSet 
join 
(
SELECT art_titel as at, COUNT(*) as Number2 
FROM artikel_views 
WHERE user_id = '' 
GROUP BY art_titel 
ORDER BY Number2 desc 
) as SecondSet 
on FirstSet.at = SecondSet.at 

我的HTML表：

<table> 
    <tr> 
    <td>Art Titel</td> 
    <td>user_id is NULL</td> 
    <td>user_id is not NULL</td> 
    </tr> 

<?php while($row = mysql_fetch_assoc($res)) { ?> 

    <tr> 
    <td><?php echo $row['at']; ?></td> 
    <td><?php echo $row['Number2']; ?></td> 
    <td><?php echo $row['Number1']; ?></td> 
    </tr> 

<?php } ?> 

</table> 

我要做的就是從$行[ '數字1']取值和$ row ['Number 2']結合art_titel。 該查詢的結果不好。在這兩個查詢中，我只有art_titel和art_titel上art_titel的匹配，但效果並不好。我需要兩種方式的所有項目。

我也試過一個聯盟，但是不是我的方式工作。

Answer 1

不需要2個查詢，只需使用CASE條件。

SELECT art_titel as at, SUM(CASE WHEN user_id != '' THEN 1 ELSE 0 END) as Number1, 
SUM(CASE WHEN user_id = '' THEN 1 ELSE 0 END) as Number2 
FROM artikel_views 
GROUP BY art_titel 
ORDER BY Number1 desc,Number2 desc