My SQL Interview Questions and Answers
How are ENUMs and SETs represented internally?
As unique integers representing the powers of two, due
to storage optimizations.
How do you start and stop MySQL on Windows?
net start MySQL, net stop MySQL
How do you start MySQL on Linux?
Explain the difference between mysql and mysql
interfaces in PHP?
mysqli is the object-oriented version of mysql library
Whatís the default port for MySQL Server?
What does tee command do in MySQL?
tee followed by a filename turns on MySQL logging to a
specified file. It can be stopped by command note.
Can you save your connection settings to a conf file?
Yes, and name it ~/.my.conf. You might want to change
the permissions on the file to 600, so that itís not
readable by others.
How do you change a password for an existing user via
mysqladmin -u root -p password "newpassword"
Use mysqldump to create a copy of the database?
mysqldump -h mysqlhost -u username -p mydatabasename >
Have you ever used MySQL Administrator and MySQL Query
Describe the tasks you accomplished with these tools.
What are some good ideas regarding user security in
There is no user without a password. There is no user
without a user name. There is no user whose Host column
contains % (which here indicates that the user can log
in from anywhere in the network or the Internet). There
are as few users as possible (in the ideal case only
root) who have unrestricted access.
Explain the difference between MyISAM Static and MyISAM
In MyISAM static all the fields have fixed width. The
Dynamic MyISAM table would include fields such as TEXT,
BLOB, etc. to accommodate the data types with various
lengths. MyISAM Static would be easier to restore in
case of corruption, since even though you might lose
some data, you know exactly where to look for the
beginning of the next record.
What does myisamchk do?
It compressed the MyISAM tables, which reduces their
Explain advantages of InnoDB over MyISAM?
Row-level locking, transactions, foreign key constraints
and crash recovery.
Explain advantages of MyISAM over InnoDB?
Much more conservative approach to disk space management
- each MyISAM table is stored in a separate file, which
could be compressed then with myisamchk if needed. With
InnoDB the tables are stored in tablespace, and not much
further optimization is possible. All data except for
TEXT and BLOB can occupy 8,000 bytes at most. No full
text indexing is available for InnoDB. TRhe COUNT(*)s
execute slower than in MyISAM due to tablespace
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