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Interview :: MySQL

61) What is the MySQL default port number?

MySQL default port number is 3306.

62) What is REGEXP?

REGEXP is a pattern match using a regular expression. The regular expression is a powerful way of specifying a pattern for a sophisticated search.

Basically, it is a special text string for describing a search pattern. To understand it better, you can think of a situation of daily life when you search for .txt files to list all text files in the file manager. The regex equivalent for .txt will be .*\.txt.

63) How many columns can you create for an index?

You can a create maximum of 16 indexed columns for a standard table.

64) What is the difference between NOW() and CURRENT_DATE()?

NOW() command is used to show current year, month, date with hours, minutes, and seconds while CURRENT_DATE() shows the current year with month and date only.

65) What is the query to display the top 20 rows?

SELECT * FROM table_name LIMIT 0,20;

66) Write a query to display the current date and time?

If you want to display the current date and time, use -

SELECT NOW();

If you want to display the current date only, use:

SELECT CURRENT_DATE();

67) What is the save point in MySQL?

A defined point in any transaction is known as savepoint.

SAVEPOINT is a statement in MySQL, which is used to set a named transaction savepoint with the name of the identifier.

68) What is SQLyog?

SQLyog program is the most popular GUI tool for admin. It is the most popular MySQL manager and admin tool. It combines the features of MySQL administrator, phpMyadmin, and others. MySQL front ends and MySQL GUI tools.

69) How do you backup a database in MySQL?

It is easy to back up data with phpMyAdmin. Select the database you want to backup by clicking the database name in the left-hand navigation bar. Then click the export button and make sure that all tables are highlighted that you want to back up. Then specify the option you want under export and save the output.

70) What are the different column comparison operators in MySQL?

The =, <>, <=, <, >=, >, <<, >>, < = >, AND, OR or LIKE operator are the comparison operators in MySQL. These operators are generally used with SELECT statement.