25 Interview Questions You should know when giving Senior PHP Developer Interview ?

1 ) What is opcache ?

2) What is PHP FPM ?

3) How PHP works Internally ?

4) What is life cycle of HTTP request ?

5) What is Singleton Design pattern ?

6 ) How Indexing Works in mysql in Detail ?

7 ) What is BTREE in index ?

8 ) What is Docker ?

9 ) What is difference between Inner and Left join ?

10 ) What is Memcache ?

11) There is page in your website running slow. How would you detect the problem and solve it?

12 ) What is multi column index ?

13 ) What are SOLID Principle in detail with Example ?

14 ) How to improve your legacy Software ?

15 ) What is EXPLAIN keyword use for in mysql ?

16 ) Write a query to find 3rd Largest Salary ?

17) How to fetch values from TestTable1 that are not in TestTable2 without using NOT keyword ?

SELECT * FROM TestTable1left join TestTable2 on TestTable1.order_num = TestTable2.order_numwhere TestTable2.order_num is null

18) What is the command used to fetch the first 5 characters of a string?

 SUBSTRING(column_name , 1 ,5 )

19) What is namespace in PHP ?

20 ) Why we use traits ?

21 ) What is JIT ?

22 ) What are new features of PHP 7 and PHP 8 ?

23 ) How can we prevent SQL-injection in PHP?

24 ) Difference between UNION VS UNION ALL ?

25 ) Are objects in PHP 5 passed by value or reference ?