Question

I have very strange error with insert query to MySQL throught PDO.

I want insert record in table if this record doesnt exists in this table yet.

$query = "INSERT INTO Phrases (KeyText)
            SELECT * FROM (SELECT :key_text) as tmp WHERE NOT EXISTS (SELECT 1 FROM Phrases WHERE KeyText = :key_text)";

    try
    {
        $preparedStatement = $db->prepare($query);
        foreach ($phrases as $phrase)
        {
            $preparedStatement->execute(array(':key_text' => $phrase));
            echo "-";
        }
    }
    catch(PDOException $e)
    {  
        echo $e->getMessage();  
    }

It throws exeption: Call to a member function execute() on a non-object.

I dont understand where is my error in SQL command. Other pieces of code is correct because when I changed SQL command to other (for example: SELECT :key_text as kt) it works correctly.

Thanks for answers.

UPDATE:
The error is:

[0] => HY000
[1] => 1096
[2] => No tables used

How can I make correct SQL command for MySQL?
Variant with

INSERT INTO Phrases (KeyText)
SELECT :key_text WHERE NOT EXISTS (SELECT 1 FROM Phrases WHERE KeyText = :key_text)

doesnt work in MySQL too.

UPDATE 2:

INSERT INTO Phrases (KeyText)
SELECT :key_text FROM DUAL WHERE NOT EXISTS (SELECT 1 FROM Phrases WHERE KeyText = :key_text)

This query with DUAL table works!

Answer 1

Your prepare call is failing, and you’ve simply assumed it succeeded.

Try

    $preparedStatement = $db->prepare($query) or die($db->errorInfo());

to catch the error.