聯接表INSERT語句

Question

我有3張桌子。 tbl_info，tbl_trainings和tbl_infotrainings，其中tbl_infotrainings用於連接tbl_info和tbl_trainings。

tbl_trainings接受多個復選框值。 tbl_trainings包含：

+------+-----------+
|  id  |  training |
+------+-----------+

tbl_infotrainings包含：

+------+-----------+---------------+
|  id  |  info_id  |  training_id  |
+------+-----------+---------------+

我的問題是插入新信息時。 這是我使用的代碼：

用於插入tbl_info的ID（可以正常工作）

$sql3 = "INSERT INTO tbl_infotrainings (info_id) (SELECT id FROM tbl_info)";

用於插入tbl_training的ID（有錯誤）

$sql4 = "INSERT INTO tbl_infotrainings (training_id) (SELECT id FROM tbl_trainings)";

數據庫中所需的輸出為：

+------+-----------+------------+
|  id  |  info_id  |  training  |
+------+-----------+------------+
|  1   |    1      |     1      |
+------+-----------+------------+
|  2   |    1      |     2      |
+------+-----------+------------+
|  3   |    1      |     3      |
+------+-----------+------------+

這是完整的代碼：

if($_POST["Submit"]=="Submit"){
$sql1="INSERT INTO tbl_info VALUES ('NULL', '$fname', '$mname', '$lname', '$street', '$barangay', '$city', '$number', '$month', '$day', '$year', '$status' , '$spouse', '$dependent')";
$result1=mysql_query($sql1);
$sql3 = "INSERT INTO tbl_infotrainings (info_id) (SELECT id FROM tbl_info)";
$result3=mysql_query($sql3);
$sql4 = "INSERT INTO tbl_infotrainings (training_id) (SELECT id FROM tbl_trainings)";
$result4=mysql_query($sql4);
    for ($i=0; $i<sizeof($checkbox);$i++){
$sql2="INSERT INTO tbl_trainings VALUES ('NULL', '".$checkbox[$i]."')";
$result2=mysql_query($sql2);    
}
}

提前致謝。

Answer 1

不要將'NULL'用作（我認為） AUTO_INCREMENT id的文本值-只需使用NULL關鍵字即可。

...
    $sql1 = "INSERT INTO tbl_info VALUES (NULL, '$fname', '$mname', '$lname', '$street', '$barangay', '$city', '$number', '$month', '$day', '$year', '$status' , '$spouse', '$dependent')"; // NULL not 'NULL'
    ...
    $sql2 = "INSERT INTO tbl_trainings VALUES (NULL, '".$checkbox[$i]."')"; // NULL not 'NULL'
...