04-02 comparison operators

01

Use these Comparison operators in WHERE

02

Comparison operators:

  • OR
  • = equals
  • <> not equal
  • > greater than
  • < less than
  • <= greater or equal to
  • >= less than or equal to

03

Example table 

DROP TABLE student;
CREATE TABLE student(
    student_id INT AUTO_INCREMENT,
    name VARCHAR(20),
    major VARCHAR(20),
    PRIMARY KEY(student_id)
);
INSERT INTO student(name,major) VALUES('John','Biology');
INSERT INTO student(name,major) VALUES('Kate','Sociology');
INSERT INTO student(name,major) VALUES('Claire','Chemistry');
INSERT INTO student(name,major) VALUES('Jack','Biology');
INSERT INTO student(name,major) VALUES('Mike','Computer Science');
SELECT * FROM student;

04

OR

Change 'Biology' and 'Chemistry' majors to 'Bio-Chemistry' 

UPDATE student
SET major = 'Bio-Chemistry'
WHERE major = 'Biology' OR major = 'Chemistry';

05

<>

Use <> for Not Equal To, 

UPDATE student
SET major = 'undecided'
WHERE name <> 'John';