pdo Prepared statements and mysql

Asked Jan 10 '17 at 13:29

Active Jan 10 '17 at 13:38

Viewed 39 times

I can't execute my sql in pdo,but it's work without pdo.

    try{
        $Attr = 'abc';
        $stmt = $dbh->prepare("ALTER TABLE num ADD COLUMN ? VARCHAR(30)");
        $stmt->bindValue(1,$Attr);
        $stmt->execute();
        print_r("<pre>");
        print_r( $stmt->errorInfo());
    }
    catch(exception $e){
        print($e->getMessage);
    }

the error info is :

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''abc' VARCHAR(30)' at line 1

But it's right when i execute my sql statement in my mysql.

ALTER TABLE num ADD COLUMN abc VARCHAR(30); -- right

then i execute this sql:

ALTER TABLE num ADD COLUMN 'abc' VARCHAR(30); -- wrong

the error info is :

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''abc' VARCHAR(30)' at line 1

the same as the first info.

so,why and how to solve ?

edited Jan 10 '17 at 13:38

Jay Blanchard

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asked Jan 10 '17 at 13:29

YXC.Coder

2

You can't bind columns/tables. – chris85 Jan 10 '17 at 13:31
http://php.net/manual/en/pdostatement.execute.php `$stmt = $dbh->prepare("ALTER TABLE num ADD COLUMN :name VARCHAR(30)"); $stmt->bindParam(':name', $Attr);` – Mirek Kowieski Jan 10 '17 at 13:32
@MirekKowieski nope, can't bind tables/columns. – chris85 Jan 10 '17 at 13:34
@chris85 Yes, that's true. He can bind tables like that `$stmt = $dbh->prepare("ALTER TABLE num ADD COLUMN $Attr VARCHAR(30)");` – Mirek Kowieski Jan 10 '17 at 13:36
1

@MirekKowieski that ^ is not considered as "binding", but "assigning". – Funk Forty Niner Jan 10 '17 at 13:37
1

@MirekKowieski nowhere a *binding* in your example can be seen – Your Common Sense Jan 10 '17 at 13:37

pdo Prepared statements and mysql

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