Is PHP deg2rad() equal to MySQL radians()?

Yes, both of these methods convert a degree value to radian. Let us create a table to understand MySQL radians. The query to create a table is as follows

mysql> create table RadiansDemo
   - > (
   - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   - > Value int
   - > );
Query OK, 0 rows affected (0.58 sec)

Insert some records in the table using insert command.

The query is as follows

mysql> insert into RadiansDemo(Value) values(0);
Query OK, 1 row affected (0.14 sec)
mysql> insert into RadiansDemo(Value) values(45);
Query OK, 1 row affected (0.17 sec)
mysql> insert into RadiansDemo(Value) values(90);
Query OK, 1 row affected (0.17 sec)

Display all records from the table using select statement.

The query is as follows

mysql> select *from RadiansDemo;

The following is the output

+----+-------+
| Id | Value |
+----+-------+
|  1 |     0 |
|  2 |    45 |
|  3 |    90 |
+----+-------+
3 rows in set (0.00 sec)

The following is the query to get the MySQL radians for degree value 0,45,90:

mysql> select radians(Value) from RadiansDemo;

The following is the output

+--------------------+
| radians(Value)     |
+--------------------+
|                  0 |
| 0.7853981633974483 |
| 1.5707963267948966 |
+--------------------+
3 rows in set (0.03 sec)

Now we will consider PHP code to check if PHP gives the same result or not. The PHP code is as follows

$firstValue = 0;
$secondValue = 45;
$ThirdValue = 90;
echo (var_dump(deg2rad($firstValue)));
echo '<br>';
echo (var_dump(deg2rad($secondValue)));
echo '<br>';
echo (var_dump(deg2rad($ThirdValue)));
echo '<br>';

The following is the output displaying both the methods give the same result in radians i.e. converting degree to radians

float(0)
float(0.78539816339745)
float(1.5707963267949)