Question

Today I encountered a bug (in PDO) I never saw before, but is kinda obvious when you think about it.

I got the following error:
Warning: PDOStatement::execute() [pdostatement.execute]: SQLSTATE[HY093]: Invalid parameter number:

The query I was using was similar to the following:

SELECT
    x
FROM
    y
WHERE
    -- CHECKING IF X = :Z --
    x = :y
AND
    1 = 2

Obviously I had more parameters and a longer query.

Why does it give me this error?

Answer 1

The solution is obvious: PDO disregards comments as such and tries to bind the non-existent variable ‘:Z’. You can’t use parameters in comments in PDO (unless you do bind them).

There’s a similar bug using question marks in comments.