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SQL ORDER BY

SQL ORDER BY Clause

ORDER BY Clause is used to sort the data on the basis of columns in ascending or descing order.

SQL ORDER BY Syntax

:

SELECT columnName1, columnName2, columnName3
from TableName ORDER By columnName1 , columnName2 ASC | DESC

Note : If We do not use the ASC or DESC keyword the Default order ASC is considered.

Suppose We Have The Following Data :

tableFull

ORDER BY DESC Example :

Example

SELECT * FROM `Users` ORDER BY ID Desc;

The Above Query Will Sort the result in descening order by Id. The Query Produces the result as :
sortIdDec

ORDER BY ASC Example :

Example

SELECT * FROM `Users` ORDER BY ID ASC;

The Above Query Will Sort the result in ascending order by Id. The Query Produces the result as :

sql order by sortAscid

ORDER BY Multiple Columns Example :

Example

SELECT * FROM `Users` ORDER BY Name, Email ASC;

The Above Query Will Sort the result in ascending order by Name & Email. The Query Produces the result as :

sortByMultipleCOl

SQL – AND & OR

SQL – AND & OR Clauses

SQL – AND & OR Explained

AND Clause :

And Clause displays the results where both the conditions are fullfilled.

OR Clause :

OR Clause displays the results where atleast one conditions is fullfilled.

Suppose we have following data :

tableFull

AND Clause Example :

Example

SELECT * FROM Users WHERE (City=”DELHI” and Name=’Riya’);

Where [City=”DELHI” and Name=’Riya’] Both Conditions are satisfied.

This Will Produce The Result As :

SQL - AND & OR

OR Clause Example :

Example

SELECT * FROM Users WHERE (City=”DELHI” OR Name=’Riya’);

Where [City=”DELHI” OR Name=’Riya’] Either condition is satisfied.

This Will Produce The Result As :

SQL - AND & OR

AND & OR Clause Together Example :

This will select the result where city is (“delhi” or name is “riya” )[produces two rows]
with the condition followed by name “linga” [Selects one from the two rows where name is “linga”]

Example

SELECT * FROM Users WHERE (City=”DELHI” OR Name=’Riya’) AND Name=’linga’;

This Will Produce The Result As :

SQL - AND & OR

SQL – WHERE Clause

SQL WHERE Clause

SQL WHERE Clause is used to filter the recoreds on the basis of some condition.
This will fetch the results which will fullfill the condition specified.

SQL WHERE Syntax :

SELECT ColumnName1,ColumnName2,ColumnName3 FROM TableName WHERE Condition

Suppose The “Users” Table has following records :

SQL WHERE Clause tableFull

Suppose we have to find those records which have ‘city’ value as “DELHI”

Example 1 – : The Following Example will fetch the results as

Example

SELECT * FROM Users WHERE city = “DELHI”;

The Above Query Will Fetch the results :

resultDelhi

Example 2 – : Fetch The Results where user’s ID is ‘5’

Example

SELECT * FROM Users WHERE ID = “5”;

The Above Query Will Produce the result as :

idResult

SQL – SELECT

SQL – SELECT Statement :

Sql Select Statement is used to fetch records from database table.

SQL – SELECT Syntax 1 (Select All Columns) :

SELECT *FROM TableName;

SQL – SELECT Syntax 2 (Select few Columns) :

SELECT ColumnName1, ColumnName2, ColumnName3,…. FROM TableName;

SQL Select All Columns Example :

Example

SELECT * FROM Users;

The above Query will display the results as :

 sql select all-c…sql-query

Select-all-c…ql-query

SQL Select Few Columns Example :

Example

SELECT ID, Name, Email FROM Users;

The above Query will display the results as :

Sql-INsert-in-Selected-columns

SQL – INSERT

SQL – INSERT Statement:

SQL INSERT INTO Statement is used to insert a new row(ie. record) in a table.

SQL INSERT INTO Syntax:

INSERT INTO TableName VALUES(Value1,Value2,….);

Note: The Above Syntax inserts rows in all columns of the table.

If You want to insert values in selected columns the following syntax is used :

INSERT INTO TableName (ColumnName1,ColumnName2,….)VALUES(Value1,Value2,….);

EXAMPLE 1 (Insert in all column) :

Example

INSERT INTO Users VALUES(‘1′,’John’,’john@yahoo.com’,’USA’,’NewYork’);

1 New row will be inserted.

Now the table has its first record after the selection it will show:

MysqlInsertStatement

EXAMPLE 2 (Insert in few columns only):

Example

INSERT INTO Users (ID,Name,Email)VALUES(‘2′,’Devid’,’david@yahoo.com’);

Note: We need to specify the column name in which we want to insert values Like If want to insert values in ID, Name and Email Columns only…

Now the table will look like:

SQL - INSERT-in-Selected-columns

Sql-Insert-in-Selected-columns

SQL – CREATE TABLE

SQL Create Table Syntax is used to create a table in database .

Tables are collection of rows & columns.

SQL – CREATE TABLE Syntax

CREATE TABLE Table_Name
(
ColumnName1 datatype,
ColumnName2 datatype,
ColumnName3 datatype,
….
….
….

);

ColumnName1, ColumnName2, ColumnName3, .. are name of columns.
datatype specifies the type of data to be stored in that column example : integer, variable , text or decimal etc..

SQL – CREATE TABLE Example

Example

CREATE TABLE Users
(
ID int,
Name varchar(100),
Email varchar(100),
Address varchar(100),
City varchar(100),
PRIMARY KEY (ID)
);

* PRIMARY KEY : Primary creates constraint on the column ID which will contain unique & not null values. We will Explain it in later topics.

Users Table will be created in CustomersDb.

To Verify the table Creation Use The following Command .

DESC TableName;

Example

DESC Users;

Which will Display Created table AS :

SQL create table

Mysql Table

SQL – Select Database

To Select database for work use the following syntax :

Syntax for SQL – Select Database

USE Keyword is used to select the database.

USE DatabaseName;

Example

USE CustomersDb;

You are now switched to database cusetomersdb.
Now you can perform actions like select , create table etc.

SQL – CREATE Database

SQL – CREATE Database Syntax is used to create a database .

Syntax for SQL – Create Database

The Sytax for CREATE Database is

CREATE Database Database_name;

Example

CREATE Database CustomersDB;

To See the Databases following command is Used.

SHOW DATABASES;

Which will Show the result as :

SQL - CREATE Database Show

My sql Show Databases

SQL – Data Types

Most Common used SQL Data types

char(n) : Fixed n numbers of characters accepted(Memory will be Allocated for n character at the time of creation). Max 8,000 characters allowed.

varchar(n) : Variable n numbers of characters accepted(Memory will be Allocated for the character at run time). Max 8,000 characters allowed.

int : Range – whole numbers from 2,147,483,648 to 2,147,483,647
bigint : Range – whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
smallint : Range – whole numbers from -32,768 32,767
tinyint : Range – whole numbers from 0 to 255
decimal : Range Allows decimal numbers from -10^38 +1 to 10^38 -1
numeric : Allows numbers from -10^38 +1 to 10^38 –1.

text : Variable character string. Maximum 2GB of text data can be accepted.
nchar : Fixed size Unicode string. Maximum 4,000 characters allowed.
nvarchar :Variable size Unicode string. Maximum 4,000 characters allowed.

datetime : Range – From 31 Jan, 1753 to Dec 31, 9999
date : Stores date a date From January 1, 0001 to December 31, 9999
time : Store a time example : 1:00 PM