Mysql Interview Question Answer

Question : 1

What is the difference between a "where" clause and a "having" clause?

Question : 2

What is the basic form of a SQL statement to read data out of a table?

Question : 3

What structure can you implement for the database to speed up table reads?

Question : 4

What are the tradeoffs with having indexes?

Question : 5

What is a "join"?

Question : 6

What is "normalization"? "Denormalization"? Why do you sometimes want to denormalize?

Question : 7

What is a "constraint"?

Question : 8

What types of index data structures can you have?

Question : 9

What is a "primary key"?

Question : 10

What is a "functional dependency"? How does it relate to database table design?

Question : 11

What is a "trigger"?

Question : 12

Why can a "group by" or "order by" clause be expensive to process?

Question : 13

What is "index covering" of a query?

Question : 14

Explain MySQL architecture.

Question : 15

Explain MySQL locks.

Question : 16

Explain multi-version concurrency control in MySQL.

Question : 17

What are MySQL transactions?

Question : 18

What is the difference between a Weak Entity and a Sub Entity?

Question : 19

What is the difference between a Weak entity and a Regular entity?

Question : 20

What is the difference between a "where" clause and a "having" clause?

Question : 21

What is the basic form of a SQL statement to read data out of a table?

Question : 22

What structure can you implement for the database to speed up table reads?

Question : 23

What are the tradeoffs with having indexes?

Question : 24

What is database?

Question : 25

Which is the subset of SQL commands used to manipulate Oracle Database structures, including tables?

Question : 26

What operator performs pattern matching?

Question : 27

What operator tests column for the absence of data?

Question : 28

What are the wildcards used for pattern matching?

Question : 29

State true or false. EXISTS, SOME, ANY are operators in SQL.

Question : 30

State true or false. !=, <>, ^= all denote the same operation.

Question : 31

What are the privileges that can be granted on a table by a user to others?

Question : 32

What command is used to get back the privileges offered by the GRANT command?

Question : 33

Which system tables contain information on privileges granted and privileges obtained?

Question : 34

Which system table contains information on constraints on all the tables created?

Question : 35

What is the difference between TRUNCATE and DELETE commands?

Question : 36

What command is used to create a table by copying the structure of another table?

Question : 37

What does the following query do? SELECT SAL + NVL(COMM,0) FROM EMP;

Question : 38

Which date function is used to find the difference between two dates?

Question : 39

Why does the following command give a compilation error?

Question : 40

What is the advantage of specifying WITH GRANT OPTION in the GRANT command?