Mysql的數列問題

Question

我想不通，它怎麼算所有這些舞者列和總所有舞者的呼應

id | dancer1 | dancer2 | dancer3 | dancer4, and so on.. 
--------------------------------------- 
1  alex  michael dalm  name 
2  clare rose  test   

我有這樣的開始，但不工作：

$counter = mysql_query("SELECT COUNT(*) AS id FROM table"); 

$num = mysql_fetch_array($counter); 
$dancers = $num["id"]; 

echo "Total dancers: $dancers"; 

任何幫助表示讚賞。謝謝！

Answer 1

完整的答案試試這個：

$counter = mysql_query("SELECT * FROM table"); 
$dancers = 0; 
while($rows = mysql_fetch_array($counter)){ 
    for($i = 1; $i <= 24; $i++){ 
     $dan_id = 'dancer'.$i; 
     if($rows[$dan_id] != "" || $rows[$dan_id] != null) 
      $dancers++; 
    } 
} 
echo "Total dancers:". $dancers; 

注：決不設計數據庫表這樣。

Answer 2

我真的保存您的舞者在不同的（容易）的方式...對於examle：

ID姓名] PHONE ....

1安娜磚石0975 ...

2傑夫·達曼0754 ...

這樣，你可以使用下面的代碼來算表：

$dancersCount="0"; 

$sql = "SELECT * FROM dancers"; 
$result = $conn->query($sql); 

if ($result->num_rows > 0) { 
    while($row = $result->fetch_assoc()) { 
    $dancersCount++; 
} 
} else { 
    echo "No dancers.."; 
} 

echo"$dancersCount"; 

計數器將它所發現的每一行時間（舞者）

如果你真的想這樣做的算+1 ...

然後，我真的不認爲有一個簡單的方法來解決這個問題......你可能會需要檢查你多少列在你的數據庫，但是這不是我可以幫你...

Answer 3

你需要改變你的表結構：

id | dancerNumber | name 
1  1    alex 
2  1    clare 
3  2    michael 
4  2    rose 
5  3    dalm 
6  3    test 
7  4    name 
8  4    dana 

SELECT COUNT(*) AS id FROM table將返回8個舞者。如果這是你正在尋找的？

如果你想保持你的結構

那麼你需要做下面的SQL查詢

SELECT dancer1, 
     dancer2, 
     dancer3, 
     (CASE WHEN (dancer1 <> "" AND dancer1 IS NOT NULL) THEN 1 ELSE 0 END + 
     CASE WHEN (dancer2 <> "" AND dancer2 IS NOT NULL) THEN 1 ELSE 0 END + 
     CASE WHEN (dancer3 <> "" AND dancer3 IS NOT NULL) THEN 1 ELSE 0 END) AS COUNTER 
FROM  table 

這將計算所有非空非空列，並在表的末尾添加計數器。這個櫃檯將包含你的結構舞者的數量。

與你的PHP代碼

$query = 'SELECT (CASE WHEN (dancer1 <> "" AND dancer1 IS NOT NULL) THEN 1 ELSE 0 END + 
       CASE WHEN (dancer2 <> "" AND dancer2 IS NOT NULL) THEN 1 ELSE 0 END + 
       CASE WHEN (dancer3 <> "" AND dancer3 IS NOT NULL) THEN 1 ELSE 0 END) AS COUNTER 
FROM table' 

$counter = mysql_query($query); 

$num = mysql_fetch_array($counter); 
$dancers = $num["COUNTER"]; 

echo "Total dancers: $dancers";