Question

我想计算一下mysql中特定字段集的字段是空的，我发现了一些例子，但它们都遍历整个表格。

基本上我有8个字段，

listing_photo_1到listing_photo_8，我想知道它们中有多少被填充。

我试过了：

$result=mysql_query("SELECT count(*) as total from listings 
                       WHERE listing_photo_1 IS NOT NULL AND 
                             listing_photo_2 IS NOT NULL AND 
                             listing_photo_3 IS NOT NULL AND 
                             listing_photo_4 IS NOT NULL AND 
                             listing_photo_5 IS NOT NULL AND 
                             listing_photo_6 IS NOT NULL AND 
                             listing_photo_7 IS NOT NULL AND 
                             listing_photo_8 IS NOT NULL AND 
                             pmpid = '$pmpid'");

$data=mysql_fetch_assoc($result);
echo $data['total'];

结果为：1

澄清我期待的结果：

listing_photo_1：已填充

listing_photo_2：已填充

listing_photo_3：已填充

listing_photo_4：空

listing_photo_5：空

listing_photo_6：空

listing_photo_7：空

listing_photo_8：empty`

结果应为3

Answer 1

WHERE listing_photo_1 IS NOT NULL AND listing_photo_2 IS NOT NULL....

修改

如果你需要获得每列的非空计数，你可以这样做

SELECT count(listing_photo_1),count(listing_photo_2),....count(listing_photo_8) from listings where pmpid = id

Count(column)将仅计算非空值。

Answer 2

您的代码尝试计算所有字段为非空的行数。您应该使用is not null而不仅仅是not null。

要计算字段数，请使用：

SELECT sum((listing_photo_1 IS NOT NULL) +
           (listing_photo_2 IS NOT NULL) +
           (listing_photo_3 IS NOT NULL) +
           (listing_photo_4 IS NOT NULL) +
           (listing_photo_5 IS NOT NULL) +
           (listing_photo_6 IS NOT NULL) +
           (listing_photo_7 IS NOT NULL) +
           (listing_photo_8 IS NOT NULL)
          ) as total
from listings
WHERE pmpid = '$pmpid';

计算行数：

SELECT count(*) as total
from listings
WHERE listing_photo_1 IS NOT NULL AND
      listing_photo_2 IS NOT NULL AND 
      listing_photo_3 IS NOT NULL AND 
      listing_photo_4 IS NOT NULL AND 
      listing_photo_5 IS NOT NULL AND 
      listing_photo_6 IS NOT NULL AND 
      listing_photo_7 IS NOT NULL AND 
      listing_photo_8 IS NOT NULL AND 
      pmpid = '$pmpid'";

编辑：

如果它们是空白的，请使用如下逻辑：

SELECT sum((listing_photo_1 IS NOT NULL and listing_photo_1 <> '') +
           (listing_photo_2 IS NOT NULL and listing_photo_2 <> '') +
           (listing_photo_3 IS NOT NULL and listing_photo_3 <> '') +
           (listing_photo_4 IS NOT NULL and listing_photo_4 <> '') +
           (listing_photo_5 IS NOT NULL and listing_photo_5 <> '') +
           (listing_photo_6 IS NOT NULL and listing_photo_6 <> '') +
           (listing_photo_7 IS NOT NULL and listing_photo_7 <> '') +
           (listing_photo_8 IS NOT NULL and listing_photo_8 <> '')
          ) as total
from listings
WHERE pmpid = '$pmpid';

计算非空字段mysql

2 个答案: