Retrieving Data Cheat Sheet < Introduction to SQL

 

Retrieving Data

SELECT

clause is used to retrieve rows from a table.

Database The database consists of a

player

table that stores the details of players who are a part of a tournament.

player

table stores the name, age and score of players.

Let's explore more about the SELECT clause using the database!

Selecting Specific Columns

To retrieve the data of only specific columns from a table, add the respective column names in the SELECT clause.

Syntax

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SELECT

column1,

column2,

...,

columnN

FROM

table_name;

SQL

Example

Let's fetch the

name

and

age

of the players from the

player

table.

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SELECT

name,

age

FROM

player;

SQL

Output

name	age
Virat	32
Rakesh	39
Sai	47
---	---

Selecting All Columns

Sometimes, we may want to select all the columns from a table. Typing out every column name, for every time we have to retrive the data, would be a pain. We have a shortcut for this!

Syntax

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SELECT *

FROM table_name;

SQL

Example

Get all the data of players from the

player

table.

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SELECT *

FROM player;

SQL

Output

name	age	score
Virat	32	50
Rakesh	39	35
Sai	47	30
---	---	---

Selecting Specific Rows

We use WHERE clause to retrieve only specific rows.

Syntax

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SELECT *

FROM table_name

WHERE condition;

SQL

WHERE

clause specifies a condition that has to be satisfied for retrieving the data from a database.

Example

Get

name

and

age

of the player whose

name

is "Ram" from the

player

table.

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SELECT *

FROM player

WHERE name="Sai";

SQL

Output

name	age	score
Sai	47	30

Try it Yourself!!

The database consists of an

employee

table that stores the

employee_id

,

name

and

salary

of employees. Let's fetch data for the following queries.

1. Get all the data from the
   employee
   table.
2. Get
   name
   and
   salary
   of all the employees from the
   employee
   table.
3. Get
   employee_id
   and
   salary
   whose
   name
   is "Raju" from the
   employee
   table.