php - mysql联合后php获取数组

Question

这个mysql语法有什么问题？我将它复制到 phpmyadmin 并完美运行。当我试图从 php 中获取数组时，它返回了“bool(false)”错误。

(
    SELECT 
        id, 
        cim, 
        'news' as kat 
    FROM 
        mbsz_news 
    WHERE 
        cim LIKE '%anystring%' 
        OR lead LIKE '%anystring%' 
        OR content LIKE '%anystring%'
) 
UNION 
(
    SELECT 
        id, 
        p_name, 
        'plaza' as kat 
    FROM 
        mbsz_plazas 
    WHERE 
        p_name LIKE '%anystring%' 
        OR uzemelteto LIKE '%anystring%'
) 
UNION 
(
    SELECT 
        id, 
        cim, 
        'book' as kat 
    FROM 
        mbsz_konyvtar 
    WHERE 
        cim LIKE '%anystring%' 
        OR kszam LIKE '%anystring%' 
        OR kiado LIKE '%anystring%'
)

PHP代码：

$res = mysql_query($sql);
while($row = mysql_fetch_array($res))
{
    echo $row['type'];
}

$res给出错误 bool(false) 感谢您的帮助。

Answer 1

您必须声明 sql 变量。例如

$sql = (
    (SELECT 
        id, 
        cim, 
        'news' as kat 
    FROM 
        mbsz_news 
    WHERE 
        cim LIKE '%anystring%' 
        OR lead LIKE '%anystring%' 
        OR content LIKE '%anystring%'
) 
UNION 
(
    SELECT 
        id, 
        p_name, 
        'plaza' as kat 
    FROM 
        mbsz_plazas 
    WHERE 
        p_name LIKE '%anystring%' 
        OR uzemelteto LIKE '%anystring%'
) 
UNION 
(
    SELECT 
        id, 
        cim, 
        'book' as kat 
    FROM 
        mbsz_konyvtar 
    WHERE 
        cim LIKE '%anystring%' 
        OR kszam LIKE '%anystring%' 
        OR kiado LIKE '%anystring%'
)

)

调用变量时，php应该可以工作吗？

$res = mysql_query($sql);
while($row = mysql_fetch_array($res))
{
    echo $row['type'];
}