The HAVING clause places conditions on the selected columns true OR false

In an SQL SELECT statement querying a single table, according to the SQL-92 standard the asterisk (*) means that:

A.all columns of the table are to be returned.B.all records meeting the full criteria are to be returned.C.all records with even partial criteria met are to be returned.D.None of the above is correct.

Answer: Option A

Explanation:

The SQL HAVING clause is used in combination with the GROUP BY clause to restrict the groups of returned rows to only those whose the condition is TRUE.

Syntax

The syntax for the HAVING clause in SQL is:

SELECT expression1, expression2, ... expression_n, 
       aggregate_function (aggregate_expression)
FROM tables
[WHERE conditions]
GROUP BY expression1, expression2, ... expression_n
HAVING condition;

Parameters or Arguments

expression1, expression2, ... expression_nExpressions that are not encapsulated within an aggregate function and must be included in the GROUP BY Clause near the end of the SQL statement.aggregate_functionThis is an aggregate function such as the SUM, COUNT, MIN, MAX, or AVG functions.aggregate_expressionThis is the column or expression that the aggregate_function will be used on.tablesThe tables that you wish to retrieve records from. There must be at least one table listed in the FROM clause.WHERE conditionsOptional. These are the conditions for the records to be selected.HAVING conditionThis is a further condition applied only to the aggregated results to restrict the groups of returned rows. Only those groups whose condition evaluates to TRUE will be included in the result set.

Example - Using SUM function

Let's look at a SQL HAVING clause example that uses the SQL SUM function.

You could also use the SQL SUM function to return the name of the department and the total sales (in the associated department). The SQL HAVING clause will filter the results so that only departments with sales greater than $1000 will be returned.

SELECT department, SUM(sales) AS "Total sales"
FROM order_details
GROUP BY department
HAVING SUM(sales) > 1000;

Example - Using COUNT function

Let's look at how we could use the HAVING clause with the SQL COUNT function.

You could use the SQL COUNT function to return the name of the department and the number of employees (in the associated department) that make over $25,000 / year. The SQL HAVING clause will filter the results so that only departments with more than 10 employees will be returned.

SELECT department, COUNT(*) AS "Number of employees"
FROM employees
WHERE salary > 25000
GROUP BY department
HAVING COUNT(*) > 10;

Example - Using MIN function

Let's next look at how we could use the HAVING clause with the SQL MIN function.

You could also use the SQL MIN function to return the name of each department and the minimum salary in the department. The SQL HAVING clause will return only those departments where the minimum salary is greater than $35,000.

SELECT department, MIN(salary) AS "Lowest salary"
FROM employees
GROUP BY department
HAVING MIN(salary) > 35000;

Example - Using MAX function

Finally, let's look at how we could use the HAVING clause with the SQL MAX function.

For example, you could also use the SQL MAX function to return the name of each department and the maximum salary in the department. The SQL HAVING clause will return only those departments whose maximum salary is less than $50,000.

SQL Having is a statement that specifies a search condition for a group or an aggregate. Having can be used only with the select statement. Having is typically used with a group by clause. When group by is not used, there is an implicit single, aggregated group. 

The Having statement enables you to specify conditions that filter which group result appear in the results.

The Where clause places conditions on the selected columns, whereas the HAVING clause places conditions on groups created by the Group By clause in Having a statement.

 

The Having statement filters records that work on summarized Group By results. The Having Statement applies to summarized group records, whereas Where applies to individual records, only the groups that meet the Having criteria will be returned. Having requires that a Group by clause is the present statement. Where and Having can be in the same query in a SQL Statement. 

A Having statement is like a Where clause, but applies only to groups as a whole (that is, to the rows in the result set representing groups), whereas the Where clause applies to individual rows. A query can contain both a Where clause and a Having clause in that case.

• The Where statement is applied first to the individual rows in the tables or table-valued objects in the Diagram pane. Only the rows that meet the conditions in the Where clause are grouped.

• The Having statement is then applied to the rows in the result set, only the groups that meet the Having conditions appear in the query output. You can apply a Having clause only to columns that also appear in the Group By statement or in an aggregate function.

The Having clause was added to SQL because the where keyword could not be used with aggregate functions in SQL Select statement.

1. SELECT column_name(s)      
2. FROM table_name      
3. WHERE condition      
4. GROUP BY column_name(s)      
5. HAVING condition      
6. ORDER BY column_name(s);
   

The following SQL statement lists if the Employees "Davolio" or "Noida" have registered more than 10 orders.

Which statement is true about the HAVING clause?

What is the HAVING clause?

Which of the following is true about HAVING and WHERE clause in SQL?

What is the use of HAVING clause in SQL?