How to use is not null sql - php

Question

my SQL CODE
$sqlNull = "SELECT primary_maths ,primary_enviornment ,primary_english
,primary_sinhala ,primary_tamil ,p_special_english ,p_a ,p_b ,p_c ,p_d ,p_e
,p_f ,p_g ,ol_maths ,ol_maths_paperClass ,ol_english ,ol_sinhala ,ol_tamil
,ol_science ,ol_history ,ol_commerce ,ol_art ,al_class_chemesty
,al_class_physics ,al_class_combindmaths ,al_class_bioscience ,al_class_economics
,al_class_businessStudies ,al_class_account ,al_class_sinhala
,al_class_logic ,al_class_buddhist ,scouting ,sp_eng ,rev_a
,rev_b ,rev_c ,rev_d ,rev_e ,rev_f ,rev_g ,rev_h ,rev_i ,rev_j
,o_a ,o_b ,o_c ,o_d ,o_e ,o_f ,o_g ,o_h ,o_i ,o_j
FROM Persons WHERE reg_id='$search' IS NOT NULL";
My PHP CODE
$sqlSubject=$dbconnect->prepare($sqlNull);
$sqlSubject->execute();
$resultFull=$sqlSubject->fetchALL(PDO::FETCH_ASSOC);
var_dump($resultFull);
now my output is
array (size=0)
empty
How to use WHERE Clause with parameter and the IS NOT NULL.I jsut have 59 columns and someof them contain NULL values.So i want to remove them when output($resultFull) coming from database.In other words i want to select where values IS NOT NULL

Answer 1

If you want an queryresult where none of the selected cols are null you have to alter you WHERE with an addional "and is not null" for every col. Just like Niels Keurentjes, Manish Jangir and Bailey S wrote above.