php - MySQL 选择，输出然后删除

Question

我在 WP 安装中使用此查询从自定义表中输出最低代码。它成功地输出了 ID 最低且取值为“0”的行。所以，这一切都很好——但是，在同一个函数中，我希望输出的代码将其设置为 1，而不是 0。我尝试了很多变体，但无法完全破解它。有任何想法吗？谢谢。

function voucher_func() {
    global $wpdb;
    $vouchers = $wpdb->get_results("SELECT MIN(code) AS code FROM vouchers WHERE taken=0");
    foreach($vouchers as $voucher){
        return $voucher->code;
    }
}
add_shortcode( 'latest_voucher', 'voucher_func' );

根据最初的建议，我已经走到这一步了。这仍然会输出正确的数据，但不会将“已获取”更新为 1

function voucher_func() {
global $wpdb;
$vouchers = $wpdb->get_results("SELECT MIN(code) AS code FROM vouchers WHERE taken=0");
foreach($vouchers as $voucher){
return $voucher->code;
}
}
$wpdb->update('vouchers', array('taken' => 1), array('code' => $voucher->code));

add_shortcode( 'latest_voucher', 'voucher_func' );

这是我现在拥有的...

function voucher_func() {
global $wpdb;
$vouchers = $wpdb->get_results("SELECT MIN(code) AS code FROM vouchers WHERE taken=0");
foreach($vouchers as $voucher){
$wpdb->update('vouchers', array('taken' => 1), array('code' => $voucher->code));
return $voucher->code;
}
}

add_shortcode( 'latest_voucher', 'voucher_func' );

这是我最终的工作代码:

function voucher_func() {
global $wpdb;
$vouchers = $wpdb->get_results("SELECT MIN(code) AS code FROM vouchers WHERE taken=0");
foreach($vouchers as $voucher){
return $voucher->code;
}
}

add_shortcode( 'latest_voucher', 'voucher_func' );

function action_wpcf7_mail_sent( $contact_form ) {
global $wpdb;
$vouchers1 = $wpdb->get_results("SELECT MIN(code) AS code FROM vouchers WHERE taken=0");
foreach($vouchers1 as $voucher1){
$wpdb->update('vouchers', array('taken' => 1), array('code' => $voucher1->code));
}
};

add_action( 'wpcf7_mail_sent', 'action_wpcf7_mail_sent', 10, 1 );

Answer 1

您需要使用 wpdb->update() :

$wpdb->update('vouchers', array('taken' => 1), array('code' => $RetrievedVoucherCode));