SQL Interview Questions 2017
There is given SQL interview questions and answers that has been requested in many organizations. For PL/square interview questions, go to our next page.
1) what is SQL ?
SQL stands for structured query language.. it is a database language used for database advent, deletion, fetching rows and enhancing rows and many others. once in a while it is reported as se-qwell.
2) when SQL appeared?
It seemed in 1974.
3) What are the usages of SQL?
- To execute queries in opposition to a database
- To retrieve statistics from a database
- To inserts data in a database
- To updates statistics in a database
- To delete statistics from a database
- To create new databases
- To create new tables in a database
- To create perspectives in a database
4) Does SQL assist programming?
No,, SQL would not have loop or Conditional assertion. it’s far used like commanding language to get right of entry to databases.
5) What are the subsets of sql?
- statistics definition language (DDL)
- statistics manipulation language (DML)
- facts manipulate language (DCL)
6) what is data definition language?
Facts definition language(DDL) allows you to CREATE, regulate and DELETE database items inclusive of schema, tables, view, series etc.
7) what’s data manipulation language?
Records manipulation language makes consumer able to get admission to and manage facts. it’s far used to carry out following operations.
- Insert records into database
- Retrieve information from the database
- update information inside the database
- Delete records from the database
8) what is facts manipulate language?
Data manage language lets in you to control get admission to to the database. It consists of two instructions supply and REVOKE.
Provide: to provide specific user to carry out precise assignment.
REVOKE: to cancel formerly denied or granted permissions.
9) What are tables and fields in database?
A desk is a fixed of prepared information. It has columns and rows. Columns can be categorized as vertical, and Rows are horizontal.
A table carries distinct variety of column known as fields however may have any number of rows that is referred to as report.
10)What is a primary key?
A primary one key is a combination of fields which uniquely specify a row. this is a unique form of particular key. primary one key values can not be NULL.