带有sql查询的PHP函数不返回值

Question

我想在php上创建一个函数，它将返回数组中sql查询的值。函数中的sql ode可以工作，我可以显示值。

但是当我想在一个函数中使用它时，它就不起作用了。我的语法中有什么错误？

function frequenz_suchen_datum_zeit($fdatum_von = "2000-01-01", $fdatum_bis = "2020-01-01", $fuhrzeit_von = "00:00:00", $fuhrzeit_bis = "23:59:59") {
$abfrage = $pdo->query("SELECT
                SUM(hg_ger_b) as hg_ger_b,
                SUM(hg_ger_v) as hg_ger_v,
                SUM(hg_zub_b) as hg_zub_b,
                SUM(hg_zub_v) as hg_zub_v,
                SUM(hg_ers_b) as hg_ers_b,
                SUM(hg_ers_v) as hg_ers_v,
                SUM(hg_rep) as hg_rep,
                SUM(pr_ger_b) as pr_ger_b,
                SUM(pr_ger_v) as pr_ger_v,
                SUM(pr_zub_b) as pr_zub_b,
                SUM(pr_zub_v) as pr_zub_v,
                SUM(pr_ers_b) as pr_ers_b,
                SUM(pr_ers_v) as pr_ers_v,
                SUM(pr_rep) as pr_rep,
                SUM(so_ser) as so_ser, 
                SUM(so_mie) as so_mie,
                SUM(so_was) as so_was,
                SUM(so_wer) as so_wer,
                SUM(so_web) as so_web
                FROM frequenz WHERE datum BETWEEN '".$fdatum_von."' AND '".$fdatum_bis."' AND uhrzeit BETWEEN '".$fuhrzeit_von."' AND '".$fuhrzeit_bis."'")->fetch();

return abfrage;
}

$test = frequenz_suchen_datum_zeit();
echo $test [hg_ger_b];

Answer 1

null

快速修复丑陋:

在函数的第一行添加:

global $pdo; 

问题:变量的范围。

请紧急查看:https://www.php.net/manual/de/language.variables.scope.php

null

function frequenz_suchen_datum_zeit($fdatum_von = "2000-01-01", $fdatum_bis = "2020-01-01", $fuhrzeit_von = "00:00:00", $fuhrzeit_bis = "23:59:59") {

global $pdo;    
$abfrage = $pdo->query("SELECT
                    SUM(hg_ger_b) as hg_ger_b,
                    SUM(hg_ger_v) as hg_ger_v,
                    SUM(hg_zub_b) as hg_zub_b,
                    SUM(hg_zub_v) as hg_zub_v,
                    SUM(hg_ers_b) as hg_ers_b,
                    SUM(hg_ers_v) as hg_ers_v,
                    SUM(hg_rep) as hg_rep,
                    SUM(pr_ger_b) as pr_ger_b,
                    SUM(pr_ger_v) as pr_ger_v,
                    SUM(pr_zub_b) as pr_zub_b,
                    SUM(pr_zub_v) as pr_zub_v,
                    SUM(pr_ers_b) as pr_ers_b,
                    SUM(pr_ers_v) as pr_ers_v,
                    SUM(pr_rep) as pr_rep,
                    SUM(so_ser) as so_ser, 
                    SUM(so_mie) as so_mie,
                    SUM(so_was) as so_was,
                    SUM(so_wer) as so_wer,
                    SUM(so_web) as so_web
                    FROM frequenz WHERE datum BETWEEN '".$fdatum_von."' AND '".$fdatum_bis."' AND uhrzeit BETWEEN '".$fuhrzeit_von."' AND '".$fuhrzeit_bis."'")->fetch();
    
    return abfrage;
    }
    
    $test = frequenz_suchen_datum_zeit();
    echo $test [hg_ger_b];