HAVING Clause
Description
The HAVING
clause is used to filter the results produced by
GROUP BY
based on the specified condition. It is often used
in conjunction with a GROUP BY
clause.
Syntax
HAVING boolean_expression
Parameters
-
boolean_expression
Specifies any expression that evaluates to a result type
boolean
. Two or more expressions may be combined together using the logical operators (AND
,OR
).Note
The expressions specified in the
HAVING
clause can only refer to:- Constants
- Expressions that appear in GROUP BY
- Aggregate functions
Examples
CREATE TABLE dealer (id INT, city STRING, car_model STRING, quantity INT);
INSERT INTO dealer VALUES
(100, 'Fremont', 'Honda Civic', 10),
(100, 'Fremont', 'Honda Accord', 15),
(100, 'Fremont', 'Honda CRV', 7),
(200, 'Dublin', 'Honda Civic', 20),
(200, 'Dublin', 'Honda Accord', 10),
(200, 'Dublin', 'Honda CRV', 3),
(300, 'San Jose', 'Honda Civic', 5),
(300, 'San Jose', 'Honda Accord', 8);
-- `HAVING` clause referring to column in `GROUP BY`.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING city = 'Fremont';
+-------+---+
| city|sum|
+-------+---+
|Fremont| 32|
+-------+---+
-- `HAVING` clause referring to aggregate function.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING sum(quantity) > 15;
+-------+---+
| city|sum|
+-------+---+
| Dublin| 33|
|Fremont| 32|
+-------+---+
-- `HAVING` clause referring to aggregate function by its alias.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING sum > 15;
+-------+---+
| city|sum|
+-------+---+
| Dublin| 33|
|Fremont| 32|
+-------+---+
-- `HAVING` clause referring to a different aggregate function than what is present in
-- `SELECT` list.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING max(quantity) > 15;
+------+---+
| city|sum|
+------+---+
|Dublin| 33|
+------+---+
-- `HAVING` clause referring to constant expression.
SELECT city, sum(quantity) AS sum FROM dealer GROUP BY city HAVING 1 > 0 ORDER BY city;
+--------+---+
| city|sum|
+--------+---+
| Dublin| 33|
| Fremont| 32|
|San Jose| 13|
+--------+---+
-- `HAVING` clause without a `GROUP BY` clause.
SELECT sum(quantity) AS sum FROM dealer HAVING sum(quantity) > 10;
+---+
|sum|
+---+
| 78|
+---+