SQL HAVING CLAUSE PAGE 32

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SQL HAVING CLAUSE

SQL HAVING CLAUSE 
The HAVING clause enables you to specify conditions that filter which group results appear in the final results. 
The WHERE clause places conditions on the selected columns, whereas the HAVING clause places conditions on groups created by the GROUP BY clause. 
Syntax: 
The following is the position of the HAVING clause in a query: 
SELECT 
FROM 
WHERE 
GROUP BY 
HAVING 
ORDER BY 
The HAVING clause must follow the GROUP BY clause in a query and must also precede the ORDER BY clause if used. The following is the syntax of the SELECT statement, including the HAVING clause: 
SELECT column1, column2 
FROM table1, table2 
WHERE [ conditions ] 
GROUP BY column1, column2 
HAVING [ conditions ] 
ORDER BY column1, column2 
Example: 
Consider the CUSTOMERS table having the following records: 
+----+----------+-----+-----------+----------+ 
| ID | NAME     | AGE | ADDRESS   | SALARY   | 
+----+----------+-----+-----------+----------+ 
|  1 | Ramakrishna  |  32 | Ahmedabad |  2000.00 | 
|  2 | Mdhu sudhan rao   |  25 | Delhi     |  1500.00 | 
|  3 | Sai  |  23 | Kota      |  2000.00 | 
|  4 | Kishor  |  25 | Mumbai    |  6500.00 | 
|  5 | Ranjith    |  27 | Bhopal    |  8500.00 | 
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|  6 | Abhi    |  22 | MP        |  4500.00 | 
|  7 | Kumar     |  24 | Indore    | 10000.00 | 
+----+----------+-----+-----------+----------+ 
Following is the example, which would display record for which similar age count would be more than or equal to 2: 
SQL > SELECT * 
FROM CUSTOMERS 
GROUP BY age 
HAVING COUNT(age) >= 2; 
This would produce the following result: 
+----+--------+-----+---------+---------+ 
| ID | NAME   | AGE | ADDRESS | SALARY  | 
+----+--------+-----+---------+---------+ 
|  2 | Mdhu sudhan rao |  25 | Delhi   | 1500.00 | 
+----+--------+-----+---------+---------+