Use of Having in SQL

Question

Hi What is the use of Having clause in SQL ?

Priya Linge · Answer

Hi 1.The SQL HAVING clause is used to restrict conditionally the output of a SQL statement by a SQL aggregate function used in your SELECT list of columns. 2.We can't specify criteria in a SQL WHERE clause against a column in the SELECT list for which SQL aggregate function is used. For example the following SQL statement will generate an error: SELECT Employee SUM (Hours) FROM EmployeeHours WHERE SUM (Hours) > 24 GROUP BY Employee 3.The SQL HAVING clause is used to do exactly this to specify a condition for an aggregate function which is used in your query: SELECT Employee SUM (Hours) FROM EmployeeHours GROUP BY Employee HAVING SUM (Hours) > 24 OutPut will be : Employee Hours John Smith 25 Tina Crown 27 Hope this will help you. Thanks.

Prashant Chaudhary · Answer

Thanks

Satyapriya Nayak · Answer

Hi Prashant The HAVING clause was added to SQL because the WHERE keyword could not be used with aggregate functions. The HAVING clause is placed near the end of the SQL statement and a SQL statement with the HAVING clause may or may not include the GROUP BY clause. The syntax for HAVING is SELECT column_name1 SUM(column_name2) FROM table_name GROUP BY column_name1 HAVING (arithmetic function condition) Note: the GROUP BY clause is optional. In our example table Store_Information Table Store_Information store_name Sales Date Los Angeles $1500 Jan-05-1999 San Diego $250 Jan-07-1999 Los Angeles $300 Jan-08-1999 Boston $700 Jan-08-1999 we would type SELECT store_name SUM(sales) FROM Store_Information GROUP BY store_name HAVING SUM(sales) > 1500 Result: store_name SUM(Sales) Los Angeles $1800 Thanks