Inserting SQL statement into PHP variable - php

Question

Im trying to insert an SQL statment into a variable. The statement contains keywords entered by the user in a search bar. However, for some reason I can keep getting the error "Trying to get the property of non-object". Below is my code:
public function searchTable() {
$sql = "SELECT grades_eng.Grade, domain_math_eng.Domain, cluster_eng.Cluster, math_standards_eng.Standard FROM ".$this->standardsTable."
WHERE Standard LIKE '%".$this->keyword." %'
INNER JOIN grades_eng ON math_standards_eng.Grade_Id = grades_eng.Id
INNER JOIN domain_math_eng ON math_standards_eng.Domain_Math_Eng_Id = domain_math_eng.Id
INNER JOIN cluster_eng ON math_standards_eng.Cluster_Eng_Id = cluster_eng.Id";
$results = $this->conn->query($sql);
//returns array
return $results;
}
The code for the object being used:
$search = new SearchResult($conn, $subject, $keyword);
$queryResults = $search->searchTable();
$search->displayResults($queryResults);
Im confident is my sql query that's causing the error because when I use the following code, it displays results :
$sql = "SELECT * FROM ".$this->standardsTable." WHERE Standard LIKE '%".$this->keyword."%' ";
$results = $this->conn->query($sql);
Im Trying to display the same results but replace the IDs with actual text. The query does work when I run it in MySql.
P.S Still working on learning to use Aliases so I apologize in advance.

Answer 1

I just learned that the "Where" keyword was suppose to go towards the end. Lesson learned!
$sql = "SELECT grades_eng.Grade, domain_math_eng.Domain, cluster_eng.Cluster, math_standards_eng.Standard FROM ".$this->standardsTable."
INNER JOIN grades_eng ON math_standards_eng.Grade_Id = grades_eng.Id
INNER JOIN domain_math_eng ON math_standards_eng.Domain_Math_Eng_Id = domain_math_eng.Id
INNER JOIN cluster_eng ON math_standards_eng.Cluster_Eng_Id = cluster_eng.Id
WHERE Standard LIKE '%".$this->keyword."%' ";