Skip to main content

Select statement with WHERE clause

WHERE Clause in SELECT Statement.
                                                        The where clause in SELECT statement is used to filter out records in table according to user constrains. It also used merge two or more by join statement. 

SELECT with WHERE
      SELECT Column-Names FROM table_name WHERE (Condition);
condition may be any 
  • Relational Condition =, <, >, !=  
  • Logical Condition AND, OR and NOT 
  • Special Operator IN, BETWEEN, ANY, ALL, SOME, EXISTS.
Example table and Statement.
Employee
 id     Emp_name      Age         Salary
 1 Jebas  35 40,000
 2             Thomas  30 80,000
 3 Mark              25 40,000
 4         Harry  42 50,000
 5 Willam      45 100,000

        SELECT Id,Emp_name FROM Employee Where id=1;  
This statement return Emp_name with row of  table  condition satisfying id =1     
 
 id     Emp_name    
 1 Jebas

        SELECT Emp_name, Salary FROM Employee Where Salary=40,000;
This statement  return Emp_name and Salary of Employee with row of table value condition satisfying salary equal to 40,000.
 id     Emp_name     Salary
 1 Jebas 40,000
 3 Mark             40,000

SELECT Statement with Logical Condition Operator.
SQL using AND
         SELECT Emp_name ,Age, Salary FROM Employee Where Age>40 AND Salary>40,000;   
This statement return Employee Name, Age, Salary with condition satisfying age greater than 40 and salary greater than 40,000.  
 Emp_name      Age         Salary
 Harry  42 50,000
 Willam  45 100,000
    
SQL using OR
         SELECT Emp_name ,Age, Salary FROM Employee  Where Age>40 OR Salary=40,000;
This statement return Employee Name, Age, Salary with condition satisfying either age greater than 40 or salary greater than 40,000. 
 Emp_name      Age         Salary
 Jebas  35 40,000
 Mark              25 40,000
 Harry  42 50,000
 Willam  45 100,000

SQL using NOT
        SELECT Emp_name FROM Employee Where Salary NOT > 35;
This statement return Employee Name with condition satisfying salary not greater than 35.
 Emp_name    
 Mark            
 Thomas

SELECT Statement with Special Operator.
SQL using IN 
        SELECT Emp_name FROM Employee WHERE Age IN(25,35);
This statement return Employee Name , whose age are in 25 and 35.
This statement can also written as
       SELECT Emp_name FROM Employee WHERE Age = 25 or Age=35;
 Emp_name    
 Jebas
 Mark            

SQL Using Between
          SELECT Emp_name,Age FROM Employee WHERE Age Between 25 and 40;
This statement return Emp_name where Employee age between 25 and 40.
 Emp_name      Age        
 Jebas  35
 Thomas  30
 Mark              25
 This statement can also written as 
SELECT Emp_name,Age FROM Employee WHERE Age > 25 and Age<= 40;
ANY, ALL, SOME, EXISTS Keyword are used with SUBQUERY will see in https://www.followlect.com/2020/06/any-all-exists-operators-in-sql-query.html post.



Thank You. Like Share and Subscribe 👍 folowlect.com

Comments