Can we use group by without having clause?

Hello there! As an expert in SQL and data manipulation, I'm here to help you understand the intricacies of SQL queries and clauses. Let's dive into the topic of using the `GROUP BY` clause without a `HAVING` clause.
SQL, or Structured Query Language, is a powerful tool for managing and manipulating relational databases. It's used by developers and analysts to extract, combine, and summarize data from databases. Two of the most commonly used clauses in SQL are `GROUP BY` and `HAVING`.
The `GROUP BY` clause groups rows that have the same values in specified columns into summary rows, like "find the total amount of sales per region" or "get the average salary per department". This is particularly useful when you want to perform aggregate functions—such as `SUM()`, `AVG()`, `MAX()`, `MIN()`, `COUNT()`—on your data.
Now, let's talk about the `HAVING` clause. The `HAVING` clause was added to SQL because the `WHERE` clause cannot be used with aggregate functions. `HAVING` is used to filter the results of a `GROUP BY` operation. It's similar to the `WHERE` clause, but it's applied after the grouping has taken place, allowing you to specify conditions on the groups themselves, not on individual rows.
**Can we use `GROUP BY` without having clause?**
Yes, you can use the `GROUP BY` clause without a `HAVING` clause. In fact, it's quite common. The `HAVING` clause is not mandatory and is used only when you need to filter the groups after they've been formed. If you're simply aggregating data without needing to filter the groups, you don't need a `HAVING` clause.
For example, if you want to find the total sales for each region, you might write a query like this:
```sql
SELECT region, SUM(sales)
FROM sales_data
GROUP BY region;
```
In this query, we're using `GROUP BY` to aggregate sales by region, but we're not using a `HAVING` clause because we want to include all regions, not just those that meet a certain condition.
However, there's an important point to note. The statement you mentioned about using `HAVING` without `GROUP BY` is referring to a specific feature in Transact-SQL (T-SQL), which is Microsoft's and Sybase's extension to SQL. T-SQL allows you to omit the `GROUP BY` clause when you're using an aggregate function in the `SELECT` list that doesn't require grouping. This is not standard SQL and won't work in all database systems.
For instance, in T-SQL, you could write:
```sql
SELECT SUM(sales) AS total_sales
FROM sales_data;
```
This query calculates the total sales for the entire table without grouping it by any column. The `SUM(sales)` function here is applied to the entire table as a single group.
In conclusion, while you can certainly use `GROUP BY` without a `HAVING` clause, the reverse is not true in standard SQL. The `HAVING` clause is optional and should be used when you need to filter groups after they've been aggregated. Always ensure that you're aware of the specific SQL dialect you're working with, as features like omitting the `GROUP BY` clause with a `HAVING` clause are not universally supported.
Now, let's proceed with the next step as per your instructions.

Using having without group by. ... You can also use the having clause with the Transact-SQL extension that allows you to omit the group by clause from a query that includes an aggregate in its select list. These scalar aggregate functions calculate values for the table as a single group, not for groups within the table.