不要在循环中对数据库进行操作

不要在循环中对数据库进行操作

性能非常低下，应改为用IN查询

示例：

1、在循环中查询数据库，增加gv_title属性(性能低下)

foreach ($res['data'] as &$val)

{

$gamesql    =   'SELECT `gv_title` FROM

`mzw_game_version` WHERE `gv_id` =

'.$val['gv_id'];

$gamequery  =   $this->db->query( $gamesql

);

$val['gv_title']        =   isset(

$gamequery->row()->gv_title ) ? $gamequery->row()->gv_title :

'';

$val['select_name_cf']          =

'';

$val['do_name_cf']

=

'';

$val['iTotalRecords']

=

$res['total'];

$val['iTotalDisplayRecords']    =

$res['total'];

$val['gc_client']

=

$arr_client[$val['gc_client']];

$val['gc_hide']

=

$arr_hide[$val['gc_is_hide']];

$val['gc_top']

=

$arr_top[$val['gc_is_top']];

$val['gc_top_time']

= date( 'Y-m-d H:i:s', $val['gc_top_time']

);

$val['gc_create_time']          =

date( 'Y-m-d H:i:s', $val['gc_create_time']

);

}

2、改用 IN 查询，速度提高至少10倍

foreach ($res['data'] as &$val)

{

$vid[]

= $val['gv_id'];

color=#ff0000>//将gv_id存入到数组

$val['select_name_cf']          =

'';

$val['do_name_cf']

=

'';

$val['iTotalRecords']

=

$res['total'];

$val['iTotalDisplayRecords']    =

$res['total'];

$val['gc_client']

=

$arr_client[$val['gc_client']];

$val['gc_hide']

=

$arr_hide[$val['gc_is_hide']];

$val['gc_top']

=

$arr_top[$val['gc_is_top']];

$val['gc_top_time']

= date( 'Y-m-d H:i:s', $val['gc_top_time']

);

$val['gc_create_time']          =

date( 'Y-m-d H:i:s', $val['gc_create_time']

);

}

if ( empty( $vid ) )    $vid =

array(0);

$vid_str    =   implode( ',', $vid

);

$sql        =   "SELECT

gv_title,gv_id FROM mzw_game_version WHERE gv_id IN ({$vid_str})";

color=#ff0000>//用IN方法对id数组进行查询

$query      =   $this->db->query( $sql

);

$title_res  =

$query->result_array();

$title_arr  =

array();

foreach ($title_res as $k => $v)

{

$title_arr[$v['gv_id']] =

$v['gv_title'];

}

foreach ($res['data'] as &$val)

{

$val['gv_title']    =

$title_arr[$val['gv_id']];

}

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