PHP，MySQL UNION查詢錯誤

Question

我在嘗試使用PHP / MySQl-AJAX調試此查詢時遇到問題：變量$ param是表單文本框上AJAX調用的結果。 本質上，我試圖對三個數據庫表（它們不幸地具有不同的字段）進行動態搜索（因此稱為concat）。 數據是具有使用不同方法生成的空間位置（對於前兩個表）的作業的地址，最后一個表是非空間數據。

            $fetch = "(SELECT JobNo AS JobNo, CONCAT(Title1, '-', Title2, '-', Title3) AS Description, 'Hurricane' as type FROM Hurricanev2 WHERE Title1 REGEXP '$param' OR Title2 REGEXP '$param' OR Title3 REGEXP '$param') 
       UNION ALL
       (SELECT jobNo AS JobNo, description As Description, address As Geocoded_address, 'geocoded' as type FROM jr WHERE description REGEXP '$param' OR address REGEXP '$param')
       UNION ALL
       (SELECT job As JobNo, description As Description, 'plan' as type FROM register WHERE description REGEXP '$param')";


    while ( $row = mysql_fetch_object( $fetch ) ) {

        $sResults .= '<tr>';
        $sResults .= '<td>' . $row['JobNo'] . '</td>';
        $sResults .= '<td>' . $row['Description'] . '</td></tr>';
    }

提前致謝

Answer 1

您不能合並具有不同列數的結果集。

嘗試以下方法；

$fetch = "(SELECT JobNo AS JobNo, CONCAT(Title1, '-', Title2, '-', Title3) AS Description, 'Hurricane' as type, 'extra' FROM Hurricanev2 WHERE Title1 REGEXP '$param' OR Title2 REGEXP '$param' OR Title3 REGEXP '$param') 
   UNION ALL
   (SELECT jobNo AS JobNo, description As Description, address As Geocoded_address, 'geocoded' as type FROM jr WHERE description REGEXP '$param' OR address REGEXP '$param')
   UNION ALL
   (SELECT job As JobNo, description As Description, 'plan' as type, 'extra' FROM register WHERE description REGEXP '$param')";

Answer 2

對於UNION，每個SELECT的列數必須相同。 嘗試在第一個和最后一個SELECT上添加一個額外的null以使輸出均勻。