I am using MySQL. Here is my schema:
Suppliers(sid: integer, sname: string, address string)
Parts(pid: integer, pname: string, color: string)
Catalog(sid: integer, pid: integer, cost: real)
(primary keys are bolded)
I am trying to write a query to select all parts that are made by at least two suppliers:
-- Find the pids of parts supplied by at least two different suppliers.
SELECT c1.pid -- select the pid
FROM Catalog AS c1 -- from the Catalog table
WHERE c1.pid IN ( -- where that pid is in the set:
SELECT c2.pid -- of pids
FROM Catalog AS c2 -- from catalog
WHERE c2.pid = c1.pid AND COUNT(c2.sid) >= 2 -- where there are at least two corresponding sids
);
First off, am I even going about this the right way?
Secondly, I get this error:
1111 — Invalid use of group function
What am I doing wrong?
When executing a query in MySQL, you may encounter an error saying Invalid use of group function when using aggregate functions like AVG(), SUM(), MAX(), MIN(), and many others.
For example, suppose you have a table named pets that keep the following records:
+----+--------+---------+------+
| id | owner | species | age |
+----+--------+---------+------+
| 1 | Jessie | bird | 2 |
| 2 | Ann | duck | 3 |
| 3 | Joe | horse | 4 |
| 4 | Mark | dog | 4 |
| 5 | Peter | dog | 5 |
+----+--------+---------+------+
From this table, you are required to query the table and show rows where the age value is smaller than the average age of all rows.
You may write a SELECT statement as follows, which triggers the Invalid use of group function error:
mysql> SELECT * FROM pets WHERE age < AVG(age);
ERROR 1111 (HY000): Invalid use of group function
The error above is because the AVG() function is used inside the WHERE clause.
Aggregate functions like AVG(), COUNT(), MAX(), MIN(), and many others can’t be used in the WHERE() clause
There are two ways you can solve this error in MySQL:
- Wrap the aggregate function call in a subquery
- Use the
HAVINGclause for the aggregate function call
This tutorial will help you learn how to do both. Let’s start with using the HAVING clause
Fix invalid use of group function with a subquery
When you need to use an aggregate function inside a WHERE clause, you need to wrap the aggregate function call in a subquery.
Returning to the pets table, you can fix the query from this:
SELECT * FROM pets WHERE age < AVG(age);
To this:
SELECT * FROM pets WHERE age < (SELECT AVG(age) FROM pets);
The average age value is 3.6, so the result set will only return rows where age is smaller than that:
+----+--------+---------+------+
| id | owner | species | age |
+----+--------+---------+------+
| 1 | Jessie | bird | 2 |
| 2 | Ann | duck | 3 |
+----+--------+---------+------+
That’s one way you can fix the invalid use of group function error. Next, let’s see how to fix the error using a HAVING clause.
Fix invalid use of group function with HAVING clause
From the same pets table above, suppose you want to find out the average age of the pets and show only pets where the average age value is greater than 2.
You may write a SELECT statement as follows:
SELECT species, AVG(age) FROM pets WHERE AVG(age) > 2 GROUP BY species;
But the query above throws the same error because aggregate functions can’t be used in the WHERE clause.
Instead of using the WHERE clause, you can use the HAVING clause as follows:
SELECT species, AVG(age) FROM pets GROUP BY species HAVING AVG(age) > 2;
Now the query should work and returns the correct result.
Conclusion
The MySQL error Invalid use of group function is caused by aggregate functions in your query that’s placed in the wrong clause.
Most likely you are placing one or more aggregate functions inside the WHERE clause, which won’t work because the WHERE clause filters the table before MySQL actually does the computation.
When you’re using a WHERE clause, the SQL query works like this:
- Filter the rows using the
WHEREclause - Compute the aggregate functions call
When MySQL runs the WHERE clause, the computation of the aggregate functions hasn’t been executed yet, so it throws an error.
When you’re using a subquery MySQL will evaluate the subquery first, so the average age value in the pets table above will be computed before selecting the rows with the WHERE clause.
Finally, the HAVING clause works like the WHERE clause, but it’s executed AFTER the computation has been done:
- Compute the aggregate functions call
- Filter the rows using the
HAVINGclause
This is why the HAVING clause can have aggregate functions while the WHERE clause can’t.
You’ve just learned how to fix the Invalid use of group function error. Nice work! 👍
I have a problem with this Query
SELECT SUM(ROUND( SUM( note=3 ) / count( note=3 ) )) AS AVG, sma_famille.famille
FROM sma_notes, sma_famille, sma_agents, sma_service_activite
WHERE sma_famille.id_famille >=14
AND sma_famille.id_service =9
AND sma_notes.id_agent >=7
GROUP BY sma_famille.id_famille
and i get the error message
#1111 - Invalid use of group function
If somebody has experience with this kind of Query.
Here some details of the query:
I i take the query without the first SUM like this (This is the whole query Code)
SELECT ROUND( SUM( note =3 ) / count( note =3 ) ) AS AVG, sma_famille.famille, sma_notes.id_agent
FROM sma_notes, sma_famille, sma_agents, sma_service_activite
WHERE sma_famille.id_famille >=14
AND sma_famille.id_service =9
AND sma_notes.id_agent >=7
AND sma_notes.id_agent = sma_agents.id_agent
AND sma_service_activite.id_activite = sma_notes.id_activite
AND sma_service_activite.id_famille = sma_famille.id_famille
GROUP BY sma_famille.id_famille, sma_notes.id_agent
Than i get results like:
AVG | famille | id_agent
3 |BEL | 7
2 |BEL | 8
1 |BEL | 9
1 |CEL | 7
2 |CEL | 8
1 |CEL | 9
But with my query who didn’t works:
SELECT SUM(ROUND( SUM( note=3 ) / count( note=3 ) )) AS AVG, sma_famille.famille
FROM sma_notes, sma_famille, sma_agents, sma_service_activite
WHERE sma_famille.id_famille >=14
AND sma_famille.id_service =9
AND sma_notes.id_agent >=7
AND sma_notes.id_agent = sma_agents.id_agent
AND sma_service_activite.id_activite = sma_notes.id_activite
AND sma_service_activite.id_famille = sma_famille.id_famille
GROUP BY sma_famille.id_famille
i want to get this result:
AVG | famille
6 |BEL
4 |CEL
Thanks in advance
Achillix
Cheers
The ERROR 1111 (HY000): Invalid use of group function is a common error message encountered in SQL when performing queries. This error occurs when the SELECT statement contains a non-aggregated column in the SELECT list along with an aggregate function, and the group by clause does not include the non-aggregated column. The purpose of the group by clause is to group rows that have the same values in specified columns, so that an aggregate function can be applied to each group. If a non-aggregated column is not included in the group by clause, the query will not be able to determine which value should be returned for that column, hence the error message.
Method 1: Include non-aggregated column in the GROUP BY clause
To fix the error «ERROR 1111 (HY000): Invalid use of group function» in SQL, you can include non-aggregated columns in the GROUP BY clause. This will ensure that the query groups the data correctly and avoids the error.
Here is an example SQL query that causes the error:
SELECT id, name, MAX(salary)
FROM employees
GROUP BY id;To fix this error, we need to include the non-aggregated column «name» in the GROUP BY clause:
SELECT id, name, MAX(salary)
FROM employees
GROUP BY id, name;Another example query that causes the same error:
SELECT department, COUNT(*), MAX(salary)
FROM employees
GROUP BY department
HAVING MAX(salary) > 50000;To fix this error, we need to include the non-aggregated column «department» in the GROUP BY clause:
SELECT department, COUNT(*), MAX(salary)
FROM employees
GROUP BY department
HAVING MAX(salary) > 50000;In summary, including non-aggregated columns in the GROUP BY clause can help fix the «ERROR 1111 (HY000): Invalid use of group function» in SQL.
Method 2: Use aggregate functions in non-aggregated columns
To fix the ERROR 1111 (HY000): Invalid use of group function in SQL, you can use aggregate functions in non-aggregated columns. Here is an example:
SELECT column1, column2, SUM(column3)
FROM table1
GROUP BY column1, column2In this example, we are using the SUM function to aggregate the values in column3. However, we are also selecting column1 and column2, which are non-aggregated columns. This will cause the ERROR 1111 (HY000) to occur.
To fix this, we can also use an aggregate function on the non-aggregated columns. Here is the updated example:
SELECT column1, MAX(column2), SUM(column3)
FROM table1
GROUP BY column1In this example, we are using the MAX function to aggregate the values in column2. This allows us to include it in the SELECT statement without causing the ERROR 1111 (HY000) to occur.
Another way to fix this issue is to use a subquery. Here is an example:
SELECT column1, column2, column3
FROM table1
WHERE column3 = (SELECT MAX(column3) FROM table1 WHERE column1 = t1.column1)In this example, we are using a subquery to find the maximum value of column3 for each value of column1. We then use this value to filter the results in the outer query.
Overall, using aggregate functions on non-aggregated columns or using subqueries can help you fix the ERROR 1111 (HY000): Invalid use of group function in SQL.
Method 3: Use a subquery or derived table to pre-aggregate data
To fix the «ERROR 1111 (HY000): Invalid use of group function» in SQL, you can use a subquery or derived table to pre-aggregate data. Here’s an example:
SELECT *
FROM (
SELECT user_id, COUNT(*) as num_orders
FROM orders
GROUP BY user_id
) AS subquery
WHERE subquery.num_orders > 5;In this example, we first create a subquery that groups the orders table by user_id and counts the number of orders for each user. We then use this subquery as a derived table and filter the results to only show users with more than 5 orders.
Another example:
SELECT *
FROM (
SELECT category_id, AVG(price) as avg_price
FROM products
GROUP BY category_id
) AS subquery
WHERE subquery.avg_price > 50;In this example, we create a subquery that groups the products table by category_id and calculates the average price for each category. We then use this subquery as a derived table and filter the results to only show categories with an average price greater than 50.
Using a subquery or derived table to pre-aggregate data can help avoid the «Invalid use of group function» error by performing the aggregation before using any group functions in the outer query.
Sometimes while running SQL queries with GROUP BY clause in MySQL, you may get an error saying ‘Invalid Use of Group Function’. This is a common problem while using aggregation functions such as AVG(), SUM(), MAX(), MIN(), and others. In this article, we will learn how to fix invalid use of group function error in MySQL.
Let us say you have MySQL table sales(id, order_datetime, amount)
mysql> create table sales(id int, order_datetime datetime, amount int);
mysql> insert into sales(id, order_datetime, amount)
values(1, '2022-01-01 10:30:30', 180),
(2, '2022-01-01 10:35:50', 100),
(3, '2022-01-01 11:50:30', 280),
(4, '2022-01-01 11:55:30', 150),
(5, '2022-01-01 12:30:30', 120),
(6, '2022-01-01 13:30:30', 100),
...
Let us say you run the following query. You will get the error mentioned below.
mysql> SELECT * FROM sales WHERE amount < AVG(amount); ERROR 1111 (HY000): Invalid use of group function
You get this error because you used an aggregate function avg() in WHERE clause. You cannot use aggregate functions in WHERE clause. This is because WHERE clause is evaluated before the aggregate function and so MySQL tries to filter the rows using WHERE clause’s condition first. While evaluating the WHERE clause for each row MySQL tries to retrieve the value of aggregate function. Since it hasn’t been computed yet, this gives an error.
There are a couple of ways to fix this problem.
1. Using HAVING clause
Instead you need to use it in HAVING clause after GROUP BY clause. Aggregate functions are applied to each group and HAVING clause is used to filter these groups further as per user requirement.
mysql> SELECT id, date(order_datetime), AVG(amount) FROM sales GROUP BY date(order_datetime) HAVING AVG(amount) > 100;
The above query will calculate average sales amount for each group (day) and filter those groups where average>100.
2. Using Subquery
Another way to fix this problem by using a subquery, where we use aggregate function inside a subquery. Here is an example.
mysql> SELECT * FROM sales WHERE amount < (SELECT AVG(amount) FROM sales);
In the above query, the subquery is first evaluated to return the average value of amount column from sales table. Then the outer query is evaluated where each row’s amount value is compared with this average value and only those rows are returned where the amount < average.
In this article, we have learnt how to fix invalid use of group function. As mentioned earlier, this mainly happens because of misplaced aggregate function, used in a WHERE clause instead of HAVING clause.
Also read:
How to Insert Current Date/Time in PostgreSQL
How to Insert Current Date/Time in MySQL
How to Uninstall MySQL Completely in Ubuntu
How to View MySQL Query Locking Table
How to Group By Date on Datetime Column