Oracle HAVING

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In Oracle, HAVING Clause is used with GROUP BY Clause to restrict the groups of returned rows where condition is TRUE.

Syntax:

  1. SELECT expression1, expression2, ... expression_n,   
  2.  aggregate_function (aggregate_expression)  
  3. FROM tables  
  4. WHERE conditions  
  5. GROUP BY expression1, expression2, ... expression_n  
  6. HAVING having_condition;   

Parameters:

expression1, expression2, ... expression_n: It specifies the expressions that are not encapsulated within aggregate function. These expressions must be included in GROUP BY clause.

aggregate_function: It specifies the aggregate functions i.e. SUM, COUNT, MIN, MAX or AVG functions.

aggregate_expression: It specifies the column or expression on that the aggregate function is based on.

tables: It specifies the table from where you want to retrieve records.

conditions: It specifies the conditions that must be fulfilled for the record to be selected.

having_conditions: It specifies the conditions that are applied only to the aggregated results to restrict the groups of returned rows.

Oracle HAVING Example: (with GROUP BY SUM function)

Let's take a table "salesdepartment"

Salesdepartment table:

  1. CREATE TABLE  "SALESDEPARTMENT"   
  2.    (    "ITEM" VARCHAR2(4000),   
  3.     "SALE" NUMBER,   
  4.     "BILLING_ADDRESS" VARCHAR2(4000)  
  5.    )  
  6. /  

oracle having example 1

Execute this query:

  1.    
  2. SELECT item, SUM(sale) AS "Total sales"  
  3. FROM salesdepartment  
  4. GROUP BY item  
  5. HAVING SUM(sale) < 1000;  

Output:

oracle having example 2

Oracle HAVING Example: (with GROUP BY COUNT function)

Let's take a table "customers"

Customer table:

  1. CREATE TABLE  "CUSTOMERS"   
  2.    (    "NAME" VARCHAR2(4000),   
  3.     "AGE" NUMBER,   
  4.     "SALARY" NUMBER,   
  5.     "STATE" VARCHAR2(4000)  
  6.    )  
  7. /  

oracle having example 3

Execute this query:

  1. SELECT state, COUNT(*) AS "Number of customers"  
  2. FROM customers  
  3. WHERE salary > 10000  
  4. GROUP BY state  
  5. HAVING COUNT(*) >= 2;  

Output:

oracle having example 4

Oracle HAVING Example: (with GROUP BY MIN function)

Let's take a table "employees"

Employees table:

  1. CREATE TABLE  "EMPLOYEES"   
  2.    (    "EMP_ID" NUMBER,   
  3.     "NAME" VARCHAR2(4000),   
  4.     "AGE" NUMBER,   
  5.     "DEPARTMENT" VARCHAR2(4000),   
  6.     "SALARY" NUMBER  
  7.    )  
  8. /  

oracle having example 5

Execute this query:

  1. SELECT department,   
  2. MIN(salary) AS "Lowest salary"  
  3. FROM employees  
  4. GROUP BY department  
  5. HAVING MIN(salary) < 15000;  

Output

oracle having example 6

Oracle HAVING Example: (with GROUP BY MAX function)

Execute this query:

  1. SELECT department,  
  2. MAX(salary) AS "Highest salary"  
  3. FROM employees  
  4. GROUP BY department  
  5. HAVING MAX(salary) > 30000;  

Output:

oracle having example 7