Question

"select " . TABLE_PREFIX.DB_USERTABLE . "." . DB_USERTABLE_USERID .
" userid, " . TABLE_PREFIX.DB_USERTABLE . "." . DB_USERTABLE_NAME .
" username, " . TABLE_PREFIX.DB_USERTABLE . "." . DB_USERTABLE_NAME .
" link, " . DB_AVATARFIELD .
" avatar,substring_index(substring_index(wp_usermeta.meta_value ,'"',-2),'"',1) role from  " .
TABLE_PREFIX.DB_USERTABLE .
"left join wp_usermeta on " . TABLE_PREFIX.DB_USERTABLE .
"." . DB_USERTABLE_USERID .
"= wp_usermeta.user_id  left join cometchat_status on " .
TABLE_PREFIX.DB_USERTABLE . "." . DB_USERTABLE_USERID .
" = cometchat_status.userid " . DB_AVATARTABLE .
" where (select count(*) from wp_bp_friends where (initiator_user_id='" .
$userid .
"' and friend_user_id=wp_users.ID) or (initiator_user_id=wp_users.ID and friend_user_id='" .
$userid .
"'))=1 and wp_usermeta.meta_key = 'wp_capabilities' order by username asc"

子字符串有错误如何避免。

Answer 1

问题在于声明的这一部分：

" avatar,substring_index(substring_index(wp_usermeta.meta_value ,'"',-2),'"',1) role from  "

您正在使用"来分隔PHP字符串，但在其中您尝试使用包含"的SQL字符串。嵌入的引用是终止PHP字符串。您需要转义嵌入式引号：

" avatar,substring_index(substring_index(wp_usermeta.meta_value ,'\"',-2),'\"',1) role from  "

Answer 2

MySQL语句中有"个双引号。这些由PHP解释为关闭字符串，因此您需要转义它们：\"

"select ".TABLE_PREFIX.DB_USERTABLE.".".DB_USERTABLE_USERID." userid, ".TABLE_PREFIX.DB_USERTABLE.".".DB_USERTABLE_NAME." username, ".TABLE_PREFIX.DB_USERTABLE.".".DB_USERTABLE_NAME." link, ".DB_AVATARFIELD." avatar,substring_index(substring_index(wp_usermeta.meta_value ,'\"',-2),'\"',1) role from  ".TABLE_PREFIX.DB_USERTABLE."left join wp_usermeta on ".TABLE_PREFIX.DB_USERTABLE.".".DB_USERTABLE_USERID."= wp_usermeta.user_id  left join cometchat_status on ".TABLE_PREFIX.DB_USERTABLE.".".DB_USERTABLE_USERID." = cometchat_status.userid ".DB_AVATARTABLE." where (select count(*) from wp_bp_friends where (initiator_user_id='".$userid."' and friend_user_id=wp_users.ID) or (initiator_user_id=wp_users.ID and friend_user_id='".$userid."'))=1 and wp_usermeta.meta_key = 'wp_capabilities' order by username asc"

Answer 3

您必须在此代码中转义双引号：

"avatar,substring_index(substring_index(wp_usermeta.meta_value ,'"',-2),'"',1) role from "

将其转换为：

"avatar,substring_index(substring_index(wp_usermeta.meta_value ,'\"',-2),'\"',1) role from "

您的代码中还有另一个短语，您必须在其中转义双引号。你必须像这样逃避它，仔细看看你会设法做到这一点。

Answer 4

问题在于这一部分：

" avatar,substring_index(substring_index(wp_usermeta.meta_value ,'"',-2),'"',1) role from  " .

double-quoted string内有双引号。那些必须使用反斜杠进行转义：

" avatar,substring_index(substring_index(wp_usermeta.meta_value ,'\"',-2),'\"',1) role from  " .

但是，在构建这样的复杂字符串时，我强烈建议您使用Heredoc语法来提高可读性。它可能看起来像这样：

<?php

  $utable = TABLE_PREFIX.DB_USERTABLE;
  $uid = DB_USERTABLE_USERID;
  $uname = DB_USERTABLE_NAME;
  $atable = DB_AVATARTABLE;
  $afield = DB_AVAYATFIELD;

  echo <<<_
select $utable.$uid
    userid, $utable.$uname
    username, $utable.$uname
    link, $afield
    avatar,substring_index(substring_index(wp_usermeta.meta_value ,'"',-2),'"',1)
role from $utable
left join wp_usermeta on $utable.$uid = wp_usermeta.user_id
left join cometchat_status on $utable.$uid = cometchat_status.userid $atable
where
    (select count(*) from wp_bp_friends
       where (initiator_user_id='$userid' and friend_user_id=wp_users.ID)
          or (initiator_user_id=wp_users.ID and friend_user_id='$userid')
    )=1
    and wp_usermeta.meta_key = 'wp_capabilities' order by username asc
_;

请注意constants未在Heredoc内展开，因此您必须先将它们存储在变量中。

如果您愿意，可以使用更具可读性的内容替换结束标识符（_），例如ENDSQL或类似内容。

解析错误：语法错误，意外''， - 2），''（T_CONSTANT_ENCAPSED_STRING），期待'，'或';'

4 个答案: