Question

我在向查询添加COUNT时遇到问题。
查询工作正常但是只要我添加 COUNT（*）AS totalNum ，我就会得到1个结果每个表

$query = "(SELECT 'table1' AS tablename, navid, thumb, title, longText, clicks AS allClicks, COUNT(*) AS totalNum
FROM table1 
WHERE $column=1 
AND enabled=1)

UNION DISTINCT

(SELECT 'table2' AS tablename, navid, thumb, title, longText, clicks AS allClicks, COUNT(*) AS totalNum 
FROM table2
WHERE $column=1 
AND enabled=1) 
ORDER BY allClicks DESC";


while ($row = mysql_fetch_assoc($result)){
    $navid = $row['navid'];
    $thumb = $row['thumb'];
    $tablename = $row['tablename'];
    $title = strtoupper($row['title']);

    etc...

}

问题：在我的加入查询中添加 count（*）的最佳方法是什么？

Answer 1

使用聚合函数（例如COUNT）时，需要包含GROUP BY子句：

(SELECT 
    'table1' AS tablename, 
    navid, 
    thumb, 
    title, 
    longText, 
    clicks AS allClicks, 
    COUNT(*) AS totalNum
FROM table1 
WHERE 
    $column=1 
    AND enabled=1
GROUP BY navid, thumb, title, longText, clicks)

UNION DISTINCT

(SELECT 
    'table2' AS tablename, 
    navid, 
    thumb, 
    title, 
    longText, 
    clicks AS allClicks, 
    COUNT(*) AS totalNum 
FROM table2
WHERE 
    $column=1 
    AND enabled=1
GROUP BY navid, thumb, title, longText, clicks)

使用UNION php的mysql COUNT

1 个答案: