Tuesday, December 27, 2016

MySQL - WHERE statement

Welcome to our MySQL lecture..
Today we will learn about MySQL WHERE clause.

Why Used WHERE in MySQL:

When we want to search some data from a condition or any other criteria then we use MySQL WHERE clause. That means to search data from a condition, we use WHERE statement in MySQL.

Rules of Writing WHERE clause in MySQL:


   SELECT column_name,column_name
   FROM table_name
   WHERE column_name operator value;

So, look at the operator . We can use the following operator here:
 =                   --->  Equal operator
>                    --->  Greater than operator
<                    --->  Less than operator
>=                  --->  Greater than or equal operator
<=                  --->  Less than or equal operator
<>                  --->  Not Equal operator
BETWEEN   --->  To check two number using between condition
LIKE            --->  To search anything like that word
IN                 --->  To check anything in the new relation or in new condition.

Example of MySQL WHERE clause:

In our second lecture of MySQL we have created a table and which is like this :
Let Insert some data first to search as our specific condition:

  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402011', 'Jhon', 'jhon@gmail.com', 'Delhi, India');
  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402039', 'Nur', 'Nur@yahoo.com', 'Bagerhat, Bangladesh');
  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402043', 'Musa', 'Musa@yahoo.com', 'Nepal');
  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402044', 'XXX', 'xxx@yahoo.com', 'Nepal');
  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402014', 'Roshan', 'roshan@gmail.com', 'Brazil');
  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402020', 'Roshan', 'roshan_india@gmail.com', 'India');
  INSERT INTO Student (ID, Name, Email, Address) VALUES ('1402030', 'Ronin', 'ronin@gmail.com', 'Brazil');


Ok, that's enough our Student table is like now:




Query 1: Select all from Student table of student name Roshan.



SELECT *
FROM Student
WHERE name = 'Roshan';


Query 2: Select all the names from Student table of student whose address is Brazil.



SELECT Name
FROM Student
WHERE Address = 'Brazil';


Query 3: Select all from Student table whose ID is less than or equal 1402030.



SELECT *
FROM Student
WHERE ID <= '1402030';


Query 4: Select all from Student table whose ID is between 1402030 and 1402014.



SELECT *
FROM Student
WHERE ID BETWEEN '1402030' AND '1402014';



Ok, thanks for staying with us. Run the code and see the output and get the exactly what you want. Please comment if you face any problem.


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