計算並在PHP的不同列中顯示多個mysql行值

Question

我已經使用以下mysql語句來計數和檢索mysql數據庫中的多個數據庫行：

SELECT COUNT(*) FROM leavesrecords WHERE leavetype IN ('Casual','Annual','Medical') and empno = '202'  GROUP BY leavetype

但是此查詢的輸出僅包含一列，列名稱為COUNT(*) 。 該查詢返回三個計數值，我希望這些值分配PHP變量。 以下我用來獲取值的PHP代碼：

include 'database.php';
$query = "SELECT COUNT(*) FROM leavesrecords WHERE leavetype IN ('Casual','Annual','Medical') and empno = '202'  GROUP BY leavetype; ";
$stmt = $con->prepare($query);
$stmt->execute();

$num = $stmt->rowCount();
if($num>0){
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
        extract($row);
        echo $row["leavesrecords"];
    } 
}
else{ echo "";}
?>

但是這段代碼在沒有顯示單個值的情況下拋出了錯誤。 我想將這三個mysql計數分配給三個mysql變量。 我怎樣才能做到這一點？

Answer 1

您應該為thr列結果使用別名

 SELECT COUNT(*) as my_count 
 FROM leavesrecords 
 WHERE leavetype IN ('Casual','Annual','Medical') and empno = '202'  GROUP BY leavetype

並使用別名的密鑰引用該列

if($num>0){
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
        // extract($row);
        echo $row["my_count"];
    } 
}

您不應使用表名而是使用正確的列名來引用行內容

Answer 2

考慮在查詢中使用IF或CASE語句返回單行：

 SELECT sum(if(leavetype='Casual',1,0)) AS `CasualCount`,
    sum(if(leavetype='Annual',1,0)) AS `AnnualCount`,
    sum(if(leavetype='Medical',1,0)) as `MedicalCount`
FROM leaverecords
WHERE leavetype IN ('Casual','Annual','Medical') and empno = '202';

現在，您將有1行包含3個字段。