Question

我试图计算具有除“N / A”之外的值的字段数（AAA - ZZZ）。从单行显示基本信息。我有2个查询单独工作查找为SQL命令，但我希望将它们合并在一起以在foreach语句中工作。

表格结构：

ID  UserID  Date    Assignment  AAA BBB CCC DDD
1   1   1/27/2014   Test    5.25    N/A 4   N/A
2   4   1/27/2014   Test2   N/A N/A 3.5 2.75
3   1   1/29/2014   Test3   1.25    N/A N/A 4.5

例如，使用上面的信息，计数将是：

ID 1, Count = 3
ID 2, Count = 2
ID 3, Count = 1

PHP表格代码：

    foreach ($pdo->query($sql) as $row) {
         echo '<tr>';
         echo '<td>'. $row['Date'] . '</td>';
         echo '<td>'. $row['UserName'] . '</td>';
         echo '<td>'. $row['Assignment'] . '</td>';
         echo '<td>'. $row['Count'] . '</td>';
         echo '</tr>';
         }
}

检索查询：

$sql = "SELECT db_log.ID, CONCAT(db_users.FName, ' ', db_users.LName) AS UserName, db_log.Date, db_log.Assignment
FROM `db_log` 
INNER JOIN `db_users` ON 
db_log.UserID=db_users.ID 
ORDER BY `ID` DESC LIMIT 0,20";

替代查询：

$sql = "SELECT db_log.ID, CONCAT(db_users.FName, ' ', db_users.LName) AS UserName, db_log.Date, db_log.Assignment
FROM `db_log`, `db_users` 
WHERE db_log.UserID=db_users.ID 
ORDER BY `ID` DESC LIMIT 0,20";

计数查询：请注意，ID = 1应该是第一个查询的ID：

SELECT COUNT(AAA) FROM (
SELECT `AAA` FROM `db_log` WHERE `AAA` <> 'N/A' AND `ID`=1 UNION ALL
SELECT `BBB` FROM `db_log` WHERE `BBB` <> 'N/A' AND `ID`=1 UNION ALL
SELECT `CCC` FROM `db_log` WHERE `CCC` <> 'N/A' AND `ID`=1 UNION ALL
SELECT `DDD` FROM `db_log` WHERE `DDD` <> 'N/A' AND `ID`=1 UNION ALL
SELECT `EEE` FROM `db_log` WHERE `EEE` <> 'N/A' AND `ID`=1) AS A

我已经查看了联接和其他解决方法，但运气不佳。在此先感谢您的帮助：）

Answer 1

以下内容可以为您提供单个查询中非N / A字段的计数。

   SELECT id, CONCAT(db_users.FName, ' ', db_users.LName) AS UserName,
    (IF (aaa = 'N/A', 0, 1) + 
     IF (bbb = 'N/A', 0, 1) + 
     IF (ccc = 'N/A', 0, 1) + 
     IF (ddd = 'N/A', 0, 1) ) AS count
    FROM db_log
    JOIN db_users on db_log.userId = db_users.userId

我在这里设置了一个SqlFiddle来玩这个：http://sqlfiddle.com/#!2/d6990/5

SQL - 在单个查询中计算多个列和JOIN

1 个答案: