Saturday, August 29, 2020

SQL Structured query language

Learn SQL Online: SQL Training For Future SQL Developers

ALERT: The general syntax is in BLUE and the example syntax is in ORANGE

1.)First, we will create a database

CREATE DATABASE database_name

CREATE DATABASE student_database


2.)Then we will use that database, 

USE database_name

USE student_database


3.)Then we will create a table and assign the names of the columns which we want to add in our table.

CREATE TABLE table_name (column1,column2,column3...)

CREATE TABLE student_table (first_name VARCHAR(400), last_nameVARCHAR(400), class INT, section VARCHAR(400), address_city VARCHAR(400) )

ALERT: while specifying the column name, we also have to specify its data type. Like the character in first_name, last_name, section, address_city, and an integer for class columns.

In order to print the column name, this syntax will be used

Select * from table_name

Select * from student_table


4.)Now our table and the columns we want in it are ready. Finally, we can insert the student info in it.

INSERT INTO table_name

values(first name, last name, class, section, city)

INSERT INTO student_table

values('Vikas', 'Singh', 14, 'A', 'Delhi')

In order to print the this info, this syntax will be used

Select * from table_name

Select * from student_table

This way,  we can add all the student info in our student_table.


5.)UPDATE EXISTING INFO

Let's suppose, Vikas Singh is shifted from section A  to B. Now you have to update this info. So this syntax will be used.

UPDATE table_name

SET section= 'B' where first_name= 'Vikas'

Select * from the table_name


UPDATE student_table

SET section= 'B' where first_name= 'Vikas'

Select * from the student_table

6.)Print top 3 entries of the table

Select top 3 * from the student_table


7.)Print top 50% of the table

Select top 50% * from the student_table

8.)Print desired columns from the table

SELECT class, section from the table_name 


9.)Print distinct columns from the table

SELECT DISTINCT column1, column2 from the table_name 

SELECT DISTINCT class, section from the student_table







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