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-- View all clients
SELECT *
FROM clients;

-- Group by region to see total sales
SELECT region, SUM(sales) AS total_sales
FROM clients
GROUP BY region;

-- Keep only regions with total sales over 25000
SELECT region, SUM(sales) AS total_sales
FROM clients
GROUP BY region
HAVING SUM(sales) > 25000;

-- Show average sales per region
SELECT region, AVG(sales) AS avg_sales
FROM clients
GROUP BY region;

-- Keep only regions with average sales at least 6000
SELECT region, AVG(sales) AS avg_sales
FROM clients
GROUP BY region
HAVING AVG(sales) >= 6000;

-- Combine conditions:
-- total sales over 25000 AND average sales at least 6000
SELECT region,
       SUM(sales) AS total_sales,
       AVG(sales) AS avg_sales
FROM clients
GROUP BY region
HAVING SUM(sales) > 25000
   AND AVG(sales) >= 6000;

# `HAVING` Clause

The `HAVING` clause lets you **filter groups** after aggregation has been applied.

It works like `WHERE`, but specifically filters the **results of grouped data**.

<br/>

## Basic Syntax

The `HAVING` clause comes after `GROUP BY` in a `SELECT` statement.

```sql title="HAVING Syntax"
SELECT column, AGG_FUNCTION(column)
FROM table_name
GROUP BY column
HAVING condition;
```

<br/>

## Example: Regions with High Sales

Suppose you have a clients table and want to find regions where total sales exceed 25,000.

Use the `HAVING` clause to filter results **after grouping**.

```sql title="Regions with high sales"
SELECT region, SUM(sales) AS total_sales
FROM clients
GROUP BY region
HAVING SUM(sales) > 25000;
```

The HAVING clause is used to filter groups after aggregation, not individual rows before they are grouped. In contrast, the WHERE clause is used to filter rows before any grouping is applied. This distinction is crucial when dealing with SQL queries that involve groupings and aggregations.

### The HAVING clause in SQL is used to filter rows before they are grouped.

HAVING Clause

Basic Syntax

Example: Regions with High Sales

The HAVING clause in SQL is used to filter rows before they are grouped.

`HAVING` Clause