我没有太多的编码知识。如何使用元值将WordPress搜索数据库快捷码添加到前端，就像我要搜索；演示“；，metavalue（命名为serial）将显示包含单词“的数据库”；演示；。我能做的最远的事情就是显示从选择表中得到的所有值。我不打算使用任何插件。
function wpb_demo_shortcode() {
global $wpdb;
$results = $wpdb->get_results("
SELECT DISTINCT o.order_id, o.`order_item_name`, om.`meta_value` as \'bcs\',
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'2-certificate\') as \'certificate\',
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'3-serial\') as \'serial\'
FROM `wp_woocommerce_order_items` as o,
`wp_woocommerce_order_itemmeta` as om,
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
om.`meta_key` = \'bcs\'
AND
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'2-certificate\') IS NOT null
AND
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'3-serial\') IS NOT null
");
$serial = (isset( $_GET[\'$serial\'] )) ? sanitize_text_field($_GET[\'$serial\']) : \'\';
?>
<form action="" method="post">
<label for="fname">Serial number:</label><br>
<input type="text" id="$serial" name="$serial"><br>
<input type="submit" value="Submit">
</form>
<?php
$enteredSerial = $_GET[\'$serial\'];
ob_start();
echo \'<table><tr>\';
echo \'<th>Order ID</th>\';
echo \'<th>Product Name</th>\';
echo \'<th>BCS</th>\';
echo \'<th>Serial</th>\';
echo \'<th>Certificate</th>\';
echo \'</tr>\';
foreach( $results as $result ){
// Html display
echo \'<tr>\';
echo \'<td>\' . $result->order_id . \'</td>\';
echo \'<td>\' . $result->order_item_name . \'</td>\';
echo \'<td>\' . $result->bcs . \'</td>\';
echo \'<td>\' . $result->serial . \'</td>\';
echo \'<td>\' . $result->certificate . \'</td>\';
echo \'</tr>\';
}
echo \'</table>\';
}
add_shortcode(\'greeting\', \'wpb_demo_shortcode\');
我已经为元值添加了占位符（如果我是对的话）。下面的图片将显示前端的外观
最合适的回答,由SO网友:tyruei 整理而成
结果发现答案比我想象的要简单
function wpb_demo_shortcode() {
global $wpdb;
$results = $wpdb->get_results("
SELECT DISTINCT o.order_id, o.`order_item_name`, om.`meta_value` as \'bcs\',
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'2-certificate\') as \'certificate\',
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'3-serial\') as \'serial\'
FROM `wp_woocommerce_order_items` as o,
`wp_woocommerce_order_itemmeta` as om,
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
om.`meta_key` = \'bcs\'
AND
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'2-certificate\') IS NOT null
AND
(select pm.`meta_value`
from
`wp_postmeta` as pm
WHERE
o.order_item_id = om.order_item_id
AND
pm.`post_id` = o.order_id
AND
pm.`meta_key` = \'3-serial\') IS NOT null
");
$serial = (isset( $_GET[\'$serial\'] )) ? sanitize_text_field($_GET[\'$serial\']) : \'\';
?>
<form action="" method="get">
<label for="fname">Serial number:</label><br>
<input type="text" id="$serial" name="$serial" minlength="3"><br>
<input type="submit" value="Submit">
</form>
<?php
$enteredSerial = $_GET[\'$serial\'];
echo $enteredSerial;
if(!empty($enteredSerial))
{
ob_start();
echo \'<table><tr>\';
echo \'<th>Order ID</th>\';
echo \'<th>Product Name</th>\';
echo \'<th>BCS</th>\';
echo \'<th>Serial</th>\';
echo \'<th>Certificate</th>\';
echo \'</tr>\';
foreach( $results as $result ){
if (strpos($result->serial, $enteredSerial) !== false)
{// Html display
echo \'<tr>\';
echo \'<td>\' . $result->order_id . \'</td>\';
echo \'<td>\' . $result->order_item_name . \'</td>\';
echo \'<td>\' . $result->bcs . \'</td>\';
echo \'<td>\' . $result->serial . \'</td>\';
echo \'<td>\' . $result->certificate . \'</td>\';
echo \'</tr>\';
}
}
echo \'</table>\';
}
}
add_shortcode(\'greeting\', \'wpb_demo_shortcode\');
SO网友:Anjan
使用下面的代码，它可以帮助您并确保您的sql查询是正确的，然后它将正常工作。
function wpb_demo_shortcode() {
global $wpdb;
$results = $wpdb->get_results(
$wpdb->prepare("SELECT DISTINCT o.order_id, o.`order_item_name`, om.`meta_value`
as \'bcs\', (select pm.`meta_value` from `wp_postmeta`
as pm WHERE o.order_item_id = om.order_item_id
AND pm.`post_id` = o.order_id
AND pm.`meta_key` = \'2-certificate\')
as \'certificate\', (select pm.`meta_value` from `wp_postmeta`
as pm WHERE o.order_item_id = om.order_item_id
AND pm.`post_id` = o.order_id
AND pm.`meta_key` = \'3-serial\')
as \'serial\' FROM `wp_woocommerce_order_items`
as o, `wp_woocommerce_order_itemmeta`
as om, `wp_postmeta`
as pm WHERE o.order_item_id = om.order_item_id
AND pm.`post_id` = o.order_id
AND om.`meta_key` = \'bcs\'
AND (select pm.`meta_value` from `wp_postmeta`
as pm WHERE o.order_item_id = om.order_item_id
AND pm.`post_id` = o.order_id
AND pm.`meta_key` = \'2-certificate\') IS NOT null
AND (select pm.`meta_value` from `wp_postmeta` as pm WHERE o.order_item_id = om.order_item_id
AND pm.`post_id` = o.order_id
AND pm.`meta_key` = \'3-serial\') IS NOT null")
);
$serial = (isset( $_GET[\'$serial\'] )) ? sanitize_text_field($_GET[\'$serial\']) : \'\';
?>
<form action="" method="post">
<label for="fname">Serial number:</label><br>
<input type="text" id="$serial" name="$serial"><br>
<input type="submit" value="Submit">
</form>
<?php
$enteredSerial = $_GET[\'$serial\'];
ob_start();
echo \'<table><tr>\';
echo \'<th>Order ID</th>\';
echo \'<th>Product Name</th>\';
echo \'<th>BCS</th>\';
echo \'<th>Serial</th>\';
echo \'<th>Certificate</th>\';
echo \'</tr>\';
foreach( $results as $result ){
// Html display
echo \'<tr>\';
echo \'<td>\' . $result->order_id . \'</td>\';
echo \'<td>\' . $result->order_item_name . \'</td>\';
echo \'<td>\' . $result->bcs . \'</td>\';
echo \'<td>\' . $result->serial . \'</td>\';
echo \'<td>\' . $result->certificate . \'</td>\';
echo \'</tr>\';
}
echo \'</table>\';
}
add_shortcode(\'greeting\', \'wpb_demo_shortcode\');
