What is JOIN in SQL??

joins are used for select the relevant data between one or more table.


What is difference between ORDER BY and GROUP BY in SQL??

Groupby : It is a way to sub-total your results,or perform
some other ‘aggregate’ functions on them.
e.g : select sum(salary)from salary Groupby employee name.

Orderby : It is a simply a way to sort your results. it display result in assending or dessending order.
e.g : select * from customer where column name=”value” orderby column name.

What is difference between DBMS and RDBMS??

.RDBMS (relational database management system) applications store data in a tabular form.
. DBMS store data as files .However there are is tables in DBMS also, but there is no relation between the tables as in RDBMS.
.In DBMS, data is generally stored in either a hierarchical form or a navigational form.
.In RDBMS tables have an identifier called primary key and Data values will be stored in the form of tables. The relationships between these data values will be stored in the form of a table as well. Every value stored in the relational database is accessible.
.RDBMS solution is required by large sets of data whereas small sets of data can be managed by DBMS

Define SQL

SQL stands for Structured Query Language. SQL is is a special-purpose programming language designed for data held in a relational database management system.
It’s originally based upon relational algebra and tuple relational calculus, It’s consists of a data definition language(DDL) and a data manipulation language(DML).