Filter aggregated results from a GROUP BY...

SELECT    <field1>, SUM | COUNT | AVG(<field2>) AS SumField2
FROM      <schema_name>.<table_name> | <view_name>
GROUP BY  <field1>
HAVING    SUM(<field2>) > <value>;

It's like saying: "Hey, PostgreSQL; please can you find this information for me? It's in this table in this schema. When you find it, please aggregate it together and read back only the results that match this criteria"

"HAVING is to a GROUP BY as WHERE is to a SELECT"

For example, if we wanted to COUNT:

• How many products we sell by product_category
• But only if there are more than 10 products in a category

We can add a HAVING clause to the COUNT(product_category) as follows:

SELECT product_category, COUNT(product_category)
FROM "sequel-mart-schema"."Products"
GROUP BY product_category
HAVING COUNT(product_category) > 10;

We can see that because there are only 6 pot_plants they are not returned