从一个表到另一列的不同表中检索数据

Question

Trying to retrieve information from the database t_awhole and input it into a_whole. I've read up on a lot of these, but cannot find anything specific to my question.

1. The code stops where I have placed the comment //>>>>Stops here<<<<< . I used an echo statement to find that it does not pass this point.
2. This is a email confirmation function, so t_awhole's table structure is different than a_whole. Everything is the same but in t_awhole the first column is a confirmation code associated to to that user. Once they click the link in their email, the row with that confirmation code should transfer all the data from that t_awhole into a_whole. However, it should not transfer the confirmation code, but should add a new column for the number of the row (first column) as an increment, and whether the user is an admin or not (last column). Everything else will stay as it was (fN, lN, aI, eml, pss) in between that first and last row. Please tell me how to do this. Someone attempted below, but his answer was difficult to understand (although he tried and I thank him for that).

3. Finally, I am using PDO as the structure. It was originally written in mysql. I notice a colon : is used instead of a money sign $ . How do I switch this to be from sql to PDO?

     <?php include('db.php'); // passkey that got from link $pk=$_GET['pk']; $t_awhole_conf="t_awhole"; // Retrieve data from table where row that match this passkey $sql_conf1="SELECT * FROM $t_awhole_conf WHERE confirm_code ='$pk'"; $result_conf=mysql_query($sql_conf1) or die ('Error updating database: '.mysql_error()); // If successfully queried if($result_conf){ // Count how many row has this passkey $count=mysql_num_rows($result_conf); // if found this passkey in our database, retrieve data from table "t_awhole" if($count==1){ $rows=mysql_fetch_array($result_conf); $fN = $rows['fN']; // capitalizes the first letter (6-26-14) $lN = $rows['lN']; // capitalizes the first letter (6-26-14) $aI = $rows['aI']; $eml = $rows['eml']; $pss = $rows['pss']; $pss2 = $rows['pss2']; $a_whole_conf="a_whole"; // Insert data that retrieves from "t_awhole" into table "a_whole" $sql_conf2= $conn->prepare("INSERT INTO $a_whole_conf(fN, lN, aI, eml, pss, admin) VALUES ($fN, $lN, $aI, $eml, $pss, $admin)"); //>>>>Stops here<<<<< $result_conf2=$sql_conf2->execute() or die ('Error updating database: '.mysql_error()); } // if not found passkey, display message "Wrong Confirmation code" else { echo "Wrong Confirmation code"; } // if successfully moved data from table"t_awhole" to table "a_whole" displays message "Your account has been activated" and don't forget to delete confirmation code from table "t_awhole" if($result_conf2){ echo "Your account has been activated"; // Delete information of this user from table "t_awholeb" that has this passkey $sql_conf3="DELETE FROM $t_awhole_conf WHERE confirm_code = '$pk'"; $result_conf3=mysql_query($sql_conf3); } } ?> 

Answer 1

TO ANSWER THE QUESTION YOU ASKED

The colon ( : ) is used in SQL text to identify a placeholder for a named bind parameter within a prepared statement . That colon gets included in the SQL text, and value for that placeholder is provided when the SQL statement is executed.

The "money sign" identifies a PHP variable; in the string context, the variable is evaluated, and the value of the variable gets incorporated into the SQL text.

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The following is not an answer to the question you asked. But I think this will answer several other questions you should be asking...

The inclusion of "unsafe" values in PHP variables is where the "SQL Injection" vulnerability comes in, if we don't have any guarantee that the value of the variables don't contain some characters that will be interpreted as SQL. And that's exactly why the mysql interface includes the mysql_real_escape_string function. This is a "wrapper" that inspects values, and properly escapes values so that they will be seen as values, and not be interpreted as SQL syntax.

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Q: 1. The code stops where I have placed the comment //>>>>Stops here<<<<<.

A: Cool. It's not clear how you know the code "Stops here", if you're getting some sort of error or what.

We don't see any declaration or assignment for the reference to the $admin variable. We do see that we expected column pss2 to be retrieved by the SELECT. But we don't see anything be done with that, except to assign that to a PHP variable named $pss2 , and that doesn't appear to be referenced anywhere else. Curious.

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Q: 2. This is a email confirmation function, so t_awhole's table structure is different than a_whole. Everything is the same but in t_awhole the first column is a confirmation code associated to to that user. Once they click the link in their email, the row with that confirmation code should transfer all the data from that t_awhole into a_whole. However, it should not transfer the confirmation code, but should add a new column for the number of the row (first column) as an increment, and whether the user is an admin or not (last column). Everything else will stay as it was (fN, lN, aI, eml, pss) in between that first and last row.

A: Seems like an awkward design. It's not clear why you need to loop through all the individual rows returned by a SELECT (and your code is subject to SQL injection. Hopefully, "Little Bobby Tables" doesn't register... http://xkcd.com/327/ )

I'm not sure why you don't just run a single INSERT .. SELECT statement to "copy" the rows from one table to the other in one fell swoop, for example:

$sql = "INSERT INTO a_whole
             (   fN  , lN,   aI,   eml,   pss, admin)
        SELECT t.fN, t.lN, t.aI, t.eml, t.pss, '' AS admin
          FROM t_awhole t
         WHERE t.confirm_code = '" . mysql_real_escape_string($pk) "'";

(I don't see any declaration or assignment to $admin in the original code, so I replaced that reference with a literal string (zero length) in the example above.)

If you were going to do this with PDO, you could use a prepared statement with a bind placeholder. All of the SQL is the same, with the exception that we replace a reference to the value of the PHP $pk variable with a bind placeholder in the SQL text:

$sql = "INSERT INTO a_whole
             (   fN  , lN,   aI,   eml,   pss, admin)
        SELECT t.fN, t.lN, t.aI, t.eml, t.pss, '' AS admin
          FROM t_awhole t
         WHERE t.confirm_code = :pk";

Now the SQL text is a constant string, and is not subject to SQL injection.

With PDO, you'd first call the prepare() , and then call bind_param() and execute() , eg

$sth = $dbh->prepare($sql);
$sth->bindParam(':pk', $pk, PDO::PARAM_INT);
$sth->execute();

BUT ... to do that, you need to have a PDO connection (referenced as $dbh above); you can't use a mysql connection with PDO.

(If you don't check the result from each call, you'd want to set the error handling on the connection to throw an error, and use a try/catch block to catch any PDOException.)

UPDATE: actually, I see that your code only copies the first row returned from the SELECT, we don't see a normal while (fetch) loop we usually see. That was my oversight there, seeing something I expected but that wasn't there. That's my bad. Still, there's no need to retrieve the values into PHP variables, if all we are going to do with them is insert them into another table. Let the database do that, without mucking up the code with a bunch of variables we don't need.

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Q: 3. Finally, I am using PDO as the structure. It was originally written in mysql. I notice a colon : is used instead of a money sign $. Why is this and where would I switch the : for the $ in my code?

A: The code modified in the edit, is now calling functions both from the deprecated mysql interface; and PDO (per the references to PDO functions.)

It's not valid to mix mysql interface functions and PDO interface functions. You can't use PDO functions on a connection obtained using the mysql interface, etc.

This is likely why your code "stops here".

(I was a little confused earlier; I didn't see the PDO functions, all I saw was mysql functions. We're not used to seeing mysql and PDO functions mixed like this, mostly because we never see this because it's not valid.)

TO ANSWER THE QUESTION YOU ASKED

The colon ( : ) is used in SQL text to identify a placeholder for a named bind parameter within a prepared statement . That colon gets included in the SQL text, and value for that placeholder is provided when the SQL statement is executed.

The "money sign" identifies a PHP variable; in the string context, the variable is evaluated, and the value of the variable gets incorporated into the SQL text. (This is where the "SQL Injection vulnerability comes in... we don't have any guarantee that the value of that variable doesn't contain text that will be interpreted as SQL.

And that's exactly why the mysql interface includes the mysql_real_escape_string function.