Why the update command can't be executed?

Question

I simplify my problem into a simple status.

mysql> select * from `table`;
+--------+---------+
| f1     | f2      |
+--------+---------+
| hallo  | welcome |
| string | array   |
+--------+---------+
2 rows in set (0.00 sec)

I want to change the table into the following result.

mysql> select * from `table`;
+--------+-------    --+
| f1     | f2          |
+--------+---------+
| hallo  | welcomehaha |
| string | arrayhaha   |
+--------+-------    --+
2 rows in set (0.00 sec)

Here is my code.

<?php

    header("Content-Type: text/html; charset=gbk");
    $db=new PDO("mysql:host=localhost;dbname=test","root","");

$statement1=$db->prepare("select  f1,f2 from `table`");
$statement1 -> execute();
while($row=$statement1->fetch()){
    $new_content=$row["f1"];
    $new_f2=$row['f2'].'haha';
    echo $new_f2.'</br>';
    $statement2=$db->prepare("update  `table` set f2=$new_f2 where f1={$row['f1']}");
    $statement2 -> execute();
    }    
?>

The output is:

welcomehaha
arrayhaha

The value of f2 isn't changed, why isn't the update 'table' set f2=$new_f2 where f1={$row['f1']} being executed?

Because, you haven't quoted your values; they're strings. Plus, you're not checking for errors. — Funk Forty Niner, Apr 15 '15 at 13:53
`...set f2=123haha`... do you have a `123haha` field in your table? — Marc B, Apr 15 '15 at 14:03

score 0 · Accepted Answer · answered Apr 15 '15 at 13:54

0

you must but your value between single quotation '' because it is text may be it is something like that

$statement2=$db->prepare("update  `table` set f2='$new_f2' where f1='{$row['f1']}'");

answered Apr 15 '15 at 13:54

Islam Zedan

656
4
21

score 0 · Answer 2 · answered Apr 15 '15 at 14:02

0

$statement2=$db->prepare("update `table` set `f2`=concat(`f2`,'haha');");

answered Apr 15 '15 at 14:02

Professor Abronsius

33,063
5
32
46

Please provide more explanation to help the op understand instead of just giving him the answer. – Johnride Apr 15 '15 at 17:54

Why the update command can't be executed?

2 Answers2