php - how to use a specific UPDATE query if existing row is empty mysql -

php - how to use a specific UPDATE query if existing row is empty mysql -

i have searched far , wide specific case reply have seems me should work. doesn't.

i want concatenate info row in database. set if there no existing info injects filenames variable row.

if there existing info in row need append "," start can break filenames out later php on page.

here's have doesn't seem work.

$query = "update plan set plan_files = if(plan_files null,concat(plan_files, '{$filenames}'),concat(plan_files, ',{$filenames}')) plan_id='{$planid}'";

try this

$query = "update plan set plan_files = (case when plan_files null '".$filenames."' else concat(plan_files , ',".$filenames."') end ) plan_id =". $planid;

please create sure $filenames string , $planid int.

php mysql