Question

So I have a form that can get data from a database by its ID (auto-incremented column(Primary Key)) and display all fields in the <input> tags via value properties. And when I submit the form I want it to either INSERT a new row if the ID from the ID column doesn’t already exist and if it does I want to UPDATE the rest of the data in the row with the same ID.

I have been trying to research this, but no one seems to be doing the same thing I am trying to do, its always slightly different. I found a REPLACE INTO and created it like below:

$sqlString = 'REPLACE INTO coursework
SET cwID=`'. $cwID .'`,
cwTitle=`'. $cwTitle .'`,
cwContent=`'. $cwContent .'`,
cwProgress=`'. $cwProgress .'`,
cwDue=`'. $cwDue .'`;

All the $cw[] variables being content received from $_POST method.

I keep getting a Error code: 1054-Unknown column ‘6’ in ‘field list’ –
the “Unknown column ‘6’” is mysql trying to call $cwID (value of $_POST[‘cwID’]) instead of the cwID column(which is the Primary Key for my table). I feel like there is something simple and stupid I am missing but I have never used this REPLACE INTO method before.

I saw a post about INSERT IGNORE INTO and INSERT ... ON DUPLICATE KEY UPDATE but both of those sound more destructive than what I am looking for.

I just want to make sure that the table is updated if the cwID exists and the auto-increment is kept in tact, or a new row is added if there is no ID. Should I just run a SELECT query to see if it exists and INSERT/ UPDATE appropriately?

Answer 1

Replace the backticks with single quotes:

$sqlString = 
 "REPLACE INTO coursework SET cwID='$cwID', cwTitle='$cwTitle', cwContent='$cwContent', cwProgress='$cwProgress', cwDue='$cwDue'";

Also, note that " will interpolate your variables.