MySql Interview Questions for all

DBMS Interview Questions and Answers for Freshers

Question: What is database? Database is a collection of information which are stored in organised way. Question: What is DBMS? Full for of DBMS is Database Management System. It is Management System which manage the...
MySQL Interview Questions and Answers for Experienced

Question: Can I concatenate multiple MySQL rows into one field? use GROUP_CONCAT function For Example SELECT group_concat( city, '--' ) AS all_city FROM `cities`WHERE 1 LIMIT 0 , 30 Output: New York--,London--,Chicago--,Frankfurt--,Paris-- Question: How to...
Difference between inner join and outer join in MySQL

Joins are used to get the records from two OR more tables. Following are different type of joinsÂ used in mysql. Left Join Right Join Inner Join Self Join Outer Join Following are difference between Inner Join & Outer Join. Inner Join: It is used to get...
How to get a list of MySQL user accounts?

In MySQL, you can get list of user account with user details. Just execute following Query of PHPMySQL/SQL Yog/Other MySQL Tools. List of MySQL users. SELECT User...
How to delete MySQL Binary logs Files in Wamp Server?

Sometime we find our Wamp Server is talking too much space like 10GB whereas it must take less than the current size. It may be your mysql binary log files are taking too much space in...
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 2269548 for key PRIMARY

Following are few reasons with solutions: Reason 1: ID is auto-increment and primary key. id is auto filed when an record is insert. When we try to insert record with same id which is already exist in table, then such type of error comes....
Multiple column ordering in Zend Framework

There are different ways to multiple column ordering in Zend. Following are two different ways to do multiple column ordering in Zend Framework. you can use either First way OR Second...
Mysql Privileges - Types of privileages in MySql - How do I grant privileges in MySQL

There are three types of privileges in MySql Administrative privilege(s) enable users to manage operation of MySQL server. These are global because they are not specific to a particular mysql database.Â Database privileges apply to a database...
Difference Between Primary Key And Unique Key And Foreign Key And Composite Key

Primary Key Primary Key can identify a row as uniquelyÂ A table can have Â only one primary key It can't be Null Indexing added automatically to Primary key Foreign Key A FOREIGN KEY in one table reference to a Primary Key in another table A table can have...
Difference Between MyISAM and innoDB - MySQL

MySQL is Open Source database means its free to use and reliable. that's why lot of application use mysql as a database. But when we going to create Â a new database, lot of doubts comes in mind like what will be database maxsize, Database engine and...
MySQL Functions - MySQL tutorial for beginners

Following are functions which is most command used in mysql Least: Return Least value amont all SELECT LEAST(4,3,8,-1,5); Greatest: Return greatest value amont all SELECT GREATEST(4,3,8,-1,5); Interval(): takes a comparison value as its first argument. The remaining arguments...
mysqlsubqueries examples Scalar Subqueries Row Subqueries Column Subqueries Table Subqueries

It is query very similar to Normal queries in databases like It may return one column it may return more column It may return single rows It may return multiple rows OR any of above combination. SubQuries are those queries which are...
Mysql FullText Search Examples

Full-text indexes can be used only with MyISAM tables, and can be created only for varchar, char and text columns only. A FULLTEXT index definition can be given in the CREATE TABLE statement when a table is created, or added later using ALTER TABLE...
MySQL Constraint Example

Q1: Table restrict for delete, if child table have records. Q2:Â Mysql constraint restrict. Q3. How to prevent from delete a parent record, if child exists. Above all Questions have only one answer that is below with fine example. Create a table products CREATE TABLE products ( ...
MySQL Cascade Example

Q1: When parent record deleted, child must be deleted automatically. But if child record deleted, parent should not effected. Q2: I want to understand the mysql constraint cascade. Q3. How a child record deleted automatically when parent deleted. Above all Questions have only one...
Mysql-Group-Concat

Group_concat: its used to concatenate column values into a single string. Create a table CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(200) DEFAULT NULL, `country` varchar(255) DEFAULT...
MySQL Expressions

Expressions are a common element of SQL statements( statements are select, delete and update). they often occur in the where clause of select, delete & update. For Example: DELETE FROM users WHERE...
MySQL Delete Table Example

Create a table CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(200) DEFAULT NULL, `image` varchar(255) DEFAULT NULL, `company` varchar(150) DEFAULT NULL, `created` datetime...
Replace Table - Update Field, Move Records to another table MySQL

Create a table CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(200) DEFAULT NULL, `image` varchar(255) DEFAULT NULL, `company` varchar(150) DEFAULT NULL, `created` datetime...
mysql insert syntax - Add records from another table - Copy Table from one table to another

Create a table CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(200) DEFAULT NULL, `image` varchar(255) DEFAULT NULL, `company` varchar(150) DEFAULT NULL, `created` datetime...
Mysql Update Syntax - Update Multiple Records

How to create a new table?Â CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(200) DEFAULT NULL, `image` varchar(255) DEFAULT NULL, `company` varchar(150) DEFAULT NULL, `created` datetime...
What is Mysql

What is Mysql? MySQL operates in a networked environment using a client and server architecture. The central program acts as a server, and various request made to server Â is client. What are Client programs? CommunicatingÂ with...
Mysql Console Commands - Export and Import database from command line

1) Create a new Database. create database mydb 2) List of all databases. show databases 3)Create Backup of all Database. mysqldump -h localhost -u username -p password â€“all-databases > dumpAllDatabase.sql 4) Create Backup of database (database...
MySQL interview Questions and Answers For Experienced

Question: What's MySQL ?Answer: MySQL is an open source relational database management system (RDBMS) that uses Structured Query Language, the most popular language for adding, accessing, and processing data in a database. Because it is open source, anyone can download MySQL...