SQL HAVING Clause
Having clause is used with SQL Queries to give more precise condition for a statement. It is used to mention condition in Group by based SQL queries, just like WHERE clause is used with SELECT query.
Syntax for HAVING clause is,
SELECT column_name, function(column_name)
FROM table_name
WHERE column_name condition
GROUP BY column_name
HAVING function(column_name) condition
Example of SQL Statement using HAVING
Consider the following Sale table.
| oid | order_name | previous_balance | customer |
|---|
| 11 | ord1 | 2000 | Alex |
| 12 | ord2 | 1000 | Adam |
| 13 | ord3 | 2000 | Abhi |
| 14 | ord4 | 1000 | Adam |
| 15 | ord5 | 2000 | Alex |
Suppose we want to find the customer whose previous_balance sum is more than 3000.
We will use the below SQL query,
SELECT *
FROM sale GROUP BY customer
HAVING sum(previous_balance) > 3000
Result will be,
| oid | order_name | previous_balance | customer |
|---|
| 11 | ord1 | 2000 | Alex |
The main objective of the above SQL query was to find out the name of the customer who has had a previous_balance more than 3000, based on all the previous sales made to the customer, hence we get the first row in the table for customer Alex.
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