How to compare the month parts of two dates? - sql

Question

I am trying to query query the current month, here is my query:
$clients = $this->Clients;
$query = $clients->find();
if($this->Auth->user('role') !== 'admin'){
$query->where(['user_id =' => $this->Auth->user('id')]);
$query->where(['MONTH(dob) = ' => 'EXTRACT(month FROM (NOW()))']);
$query->order(['dob' => 'ASC']);
}
It returns 0 records (my field is a date type), however this query in phpmyadmin works:
SELECT * FROM `clients` WHERE MONTH(dob) = EXTRACT(month FROM (NOW()))
What am I doing wrong?

Answer 1

Just look at the actual generated query (check out your DBMS query log, or try DebugKit), it will look different, as the right hand side value in a key => value condition set is subject to parameter-binding/casting/quoting/escaping. In your case it will be treated as a string, so the condition will finally look something like:
WHERE MONTH(dob) = 'EXTRACT(month FROM (NOW()))'
That will of course not match anything.
You could pass the whole SQL snippet as a single array value, or as an expression object, that way it would be inserted into the query as is (do not insert user values that way, that would create an SQL injection vulnerability!), but I'd suggest to use portable function expressions instead.
CakePHP ships with functions expressions for EXTRACT and NOW, so you can simply do something like:
use Cake\Database\Expression\IdentifierExpression;
use Cake\Database\Expression\QueryExpression;
use Cake\ORM\Query;
// ...
$query->where(function (QueryExpression $exp, Query $query) {
return $exp->eq(
$query->func()->extract('MONTH', new IdentifierExpression('dob')),
$query->func()->extract('MONTH', $query->func()->now())
);
});
Looks a bit complicated, but it's worth it, it's cross DBMS portable as well as auto-quoting compatible. The generated SQL will look something like
WHERE EXTRACT(MONTH FROM (dob)) = (EXTRACT(MONTH FROM (NOW())))
See also
Cookbook > Database Access & ORM > Query Builder > Advanced Conditions
Cookbook > Database Access & ORM > Query Builder > Using SQL Functions
API > \Cake\Database\Expression\QueryExpression::eq()
API > \Cake\Database\FunctionsBuilder::extract()
API > \Cake\Database\FunctionsBuilder::now()