Interviews Questions And Answers

SQL Interview Questions and Answers(New) New

SQL Interview Questions And Answers
Oracle interview Questions(300).

Introduction to SQL

What is SQL?

SQL is a Standard

SQL Database Tables

SQL Queries

SQL Data Definition Language (DDL)

* CREATE TABLE
* ALTER TABLE
* DROP TABLE
* CREATE INDEX
* DROP INDEX

The SQL SELECT Statement

Select All Columns

The Result Set

Semicolon after SQL Statements?

The SELECT DISTINCT Statement
The WHERE Clause

Using Quotes

The LIKE Condition

The INSERT INTO Statement

Insert a New Row

Insert Data in Specified Columns

The Update Statement


Update one Column in a Row

Update several Columns in a Row

The DELETE statement is used to delete rows

Delete a Row

Delete All Rows

Sort the Rows

The ORDER BY clause is used to sort the rows.

AND & OR

IN

BETWEEN ... AND

Referring to Two Tables

To create a database:

Create a Table

Create Index

A Unique Index

A Simple Index

Drop Index

ALTER TABLE table_name DROP INDEX index_name


Delete a Table or Database

DROP TABLE table_name


Truncate a Table

TRUNCATE TABLE table_name
ALTER TABLE

The ALTER TABLE statement is used to add or
drop columns in an existing table.

ALTER TABLE table_name
ADD column_name datatype

ALTER TABLE table_name
DROP COLUMN column_name

Note: Some database systems don't allow the
dropping of a column in a database table
(DROP COLUMN column_name).

Person:
LastName FirstName Address
Pettersen Kari Storgt 20

Example

To add a column named "City" in the "Person"
table:

ALTER TABLE Person ADD City varchar(30)

Result:
LastName FirstName Address
City
Pettersen Kari Storgt 20
Example

To drop the "Address" column in the "Person"
table:

ALTER TABLE Person DROP COLUMN Address

Result:
LastName FirstName City
Pettersen Kari

SQL has a lot of built-in functions for
counting and calculations.
Function Syntax

The syntax for built-in SQL functions is:

SELECT function(column) FROM table


Types of Functions

* Aggregate Functions
* Scalar functions

Aggregate functions

Scalar functions

Aggregate functions
GROUP BY...


HAVING...


Make a Backup Copy

SQL CREATE VIEW Statement
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