MySql查询中的PHP变量

Question

好的，我很抱歉，我已经超出了我的深度。我不是那种依赖像这样的地方的人，任何帮助提高我的MySQL知识的非常感谢！

我有这个查询被调用来收集关于在我们的wordpress网站上注册的用户的信息。

$verified = $wpdb->get_results("SELECT wp_users.ID, wp_users.user_login, wp_users.user_nicename, wp_users.user_email, m1.meta_value AS first_name, m2.meta_value AS last_name, m3.meta_value AS address, m4.meta_value AS date_of_birth_ddmmyyyy, m5.meta_value AS do_you_consider_yourself_as_having_a_disability, m6.meta_value AS hearing_ability, m7.meta_value AS ethnic_origin, m8.meta_value AS sex, m9.meta_value AS mobile_number, m10.meta_value AS telephone_number, m11.meta_value AS postcode, m12.meta_value AS towncity, m13.meta_value AS county, m14.meta_value AS who_is_paying_for_the_course, m15.meta_value AS course_type, m16.meta_value AS start_date, m17.meta_value AS course_times, m18.meta_value AS duration, m19.meta_value AS venue, m20.meta_value AS price, m21.meta_value AS code 
FROM wp_users 
INNER JOIN wp_usermeta m ON wp_users.id = m.user_id 
AND m.meta_key = 'wp_user_level' 
AND m.meta_value =0 
LEFT JOIN wp_usermeta m1 ON wp_users.id = m1.user_id 
AND m1.meta_key = 'first_name' 
LEFT JOIN wp_usermeta m2 ON wp_users.id = m2.user_id 
AND m2.meta_key = 'last_name' 
LEFT JOIN wp_usermeta m3 ON wp_users.id = m3.user_id 
AND m3.meta_key = 'address' 
LEFT JOIN wp_usermeta m4 ON wp_users.id = m4.user_id 
AND m4.meta_key = 'date_of_birth_ddmmyyyy' 
LEFT JOIN wp_usermeta m5 ON wp_users.id = m5.user_id 
AND m5.meta_key = 'do_you_consider_yourself_as_having_a_disability' 
LEFT JOIN wp_usermeta m6 ON wp_users.id = m6.user_id 
AND m6.meta_key = 'hearing_ability' 
LEFT JOIN wp_usermeta m7 ON wp_users.id = m7.user_id 
AND m7.meta_key = 'ethnic_origin' 
LEFT JOIN wp_usermeta m8 ON wp_users.id = m8.user_id 
AND m8.meta_key = 'sex' 
LEFT JOIN wp_usermeta m9 ON wp_users.id = m9.user_id 
AND m9.meta_key = 'mobile_number' 
LEFT JOIN wp_usermeta m10 ON wp_users.id = m10.user_id 
AND m10.meta_key = 'telephone_number' 
LEFT JOIN wp_usermeta m11 ON wp_users.id = m11.user_id 
AND m11.meta_key = 'postcode' 
LEFT JOIN wp_usermeta m12 ON wp_users.id = m12.user_id 
AND m12.meta_key = 'towncity' 
LEFT JOIN wp_usermeta m13 ON wp_users.id = m13.user_id 
AND m13.meta_key = 'county' 
LEFT JOIN wp_usermeta m14 ON wp_users.id = m14.user_id 
AND m14.meta_key = 'who_is_paying_for_the_course' 
LEFT JOIN wp_usermeta m15 ON wp_users.id = m15.user_id 
AND m15.meta_key = 'course_type' 
LEFT JOIN wp_usermeta m16 ON wp_users.id = m16.user_id 
AND m16.meta_key = 'start_date' 
LEFT JOIN wp_usermeta m17 ON wp_users.id = m17.user_id 
AND m17.meta_key = 'course_times' 
LEFT JOIN wp_usermeta m18 ON wp_users.id = m18.user_id 
AND m18.meta_key = 'duration' 
LEFT JOIN wp_usermeta m19 ON wp_users.id = m19.user_id 
AND m19.meta_key = 'venue' 
LEFT JOIN wp_usermeta m20 ON wp_users.id = m20.user_id 
AND m20.meta_key = 'price' 
LEFT JOIN wp_usermeta m21 ON wp_users.id = m21.user_id 
AND m21.meta_key = 'code' 
WHERE user_login NOT LIKE '%unverified__%' 
ORDER BY course_type ASC"); 

现在我知道查询本身并不理想。但我想要做的是使用变量或其他方式来改变ORDER BY的值，这将节省文件大小（系统资源呢？），这可能吗？

例如，如果我这就是我想实现（尽管它是错的）

$verified = $wpdb->get_results("SELECT wp_users.ID, wp_users.user_login, wp_users.user_nicename, wp_users.user_email, m1.meta_value AS first_name, m2.meta_value AS last_name, m3.meta_value AS address, m4.meta_value AS date_of_birth_ddmmyyyy, m5.meta_value AS do_you_consider_yourself_as_having_a_disability, m6.meta_value AS hearing_ability, m7.meta_value AS ethnic_origin, m8.meta_value AS sex, m9.meta_value AS mobile_number, m10.meta_value AS telephone_number, m11.meta_value AS postcode, m12.meta_value AS towncity, m13.meta_value AS county, m14.meta_value AS who_is_paying_for_the_course, m15.meta_value AS course_type, m16.meta_value AS start_date, m17.meta_value AS course_times, m18.meta_value AS duration, m19.meta_value AS venue, m20.meta_value AS price, m21.meta_value AS code 
FROM wp_users 
INNER JOIN wp_usermeta m ON wp_users.id = m.user_id 
AND m.meta_key = 'wp_user_level' 
AND m.meta_value =0 
LEFT JOIN wp_usermeta m1 ON wp_users.id = m1.user_id 
AND m1.meta_key = 'first_name' 
LEFT JOIN wp_usermeta m2 ON wp_users.id = m2.user_id 
AND m2.meta_key = 'last_name' 
LEFT JOIN wp_usermeta m3 ON wp_users.id = m3.user_id 
AND m3.meta_key = 'address' 
LEFT JOIN wp_usermeta m4 ON wp_users.id = m4.user_id 
AND m4.meta_key = 'date_of_birth_ddmmyyyy' 
LEFT JOIN wp_usermeta m5 ON wp_users.id = m5.user_id 
AND m5.meta_key = 'do_you_consider_yourself_as_having_a_disability' 
LEFT JOIN wp_usermeta m6 ON wp_users.id = m6.user_id 
AND m6.meta_key = 'hearing_ability' 
LEFT JOIN wp_usermeta m7 ON wp_users.id = m7.user_id 
AND m7.meta_key = 'ethnic_origin' 
LEFT JOIN wp_usermeta m8 ON wp_users.id = m8.user_id 
AND m8.meta_key = 'sex' 
LEFT JOIN wp_usermeta m9 ON wp_users.id = m9.user_id 
AND m9.meta_key = 'mobile_number' 
LEFT JOIN wp_usermeta m10 ON wp_users.id = m10.user_id 
AND m10.meta_key = 'telephone_number' 
LEFT JOIN wp_usermeta m11 ON wp_users.id = m11.user_id 
AND m11.meta_key = 'postcode' 
LEFT JOIN wp_usermeta m12 ON wp_users.id = m12.user_id 
AND m12.meta_key = 'towncity' 
LEFT JOIN wp_usermeta m13 ON wp_users.id = m13.user_id 
AND m13.meta_key = 'county' 
LEFT JOIN wp_usermeta m14 ON wp_users.id = m14.user_id 
AND m14.meta_key = 'who_is_paying_for_the_course' 
LEFT JOIN wp_usermeta m15 ON wp_users.id = m15.user_id 
AND m15.meta_key = 'course_type' 
LEFT JOIN wp_usermeta m16 ON wp_users.id = m16.user_id 
AND m16.meta_key = 'start_date' 
LEFT JOIN wp_usermeta m17 ON wp_users.id = m17.user_id 
AND m17.meta_key = 'course_times' 
LEFT JOIN wp_usermeta m18 ON wp_users.id = m18.user_id 
AND m18.meta_key = 'duration' 
LEFT JOIN wp_usermeta m19 ON wp_users.id = m19.user_id 
AND m19.meta_key = 'venue' 
LEFT JOIN wp_usermeta m20 ON wp_users.id = m20.user_id 
AND m20.meta_key = 'price' 
LEFT JOIN wp_usermeta m21 ON wp_users.id = m21.user_id 
AND m21.meta_key = 'code' 
WHERE user_login NOT LIKE '%unverified__%' 
ORDER BY " . $MYVARIABLE ."ASC"); 

$MYVARIABLE = 'my_order_by_column_name'; 

我读的地方，你可以有一个“ORDER BY子句”但我不知道这是什么是如何使用？

任何帮助非常感谢！

克雷格

Answer 1

你有什么，只要把变量在查询看起来是正确的。然而，在执行查询之前，您需要定义变量..

$MYVARIABLE = 'my_order_by_column_name'; 

$verified = $wpdb->get_results("SELECT...ORDER BY $MYVARIABLE ASC"); 

如果$ MYVARIABLE值从用户输入的到来，我建议创建一个允许列阵列中使用用于排序并验证$ MYVARIABLE的值是其中的一列。

// columns that can be used for sorting 
$sortable = array('column1', 'column2', 'column3'); 

// make sure its a valid column, if not use the first sortable column as a default 
if (!in_array($MYVARIABLE, $sortable)) $MYVARIABLE = $sortable[0]; 

$verified = $wpdb->get_results("SELECT... ORDER BY $MYVARIABLE ASC");